Chapter 18
Indoor Plants
Bob Polomski
Learning Objectives
◆ Know how light, temperature, and relative
humidity affect plant growth.
◆ Know how to measure light intensity inside
your home.
◆ Know how plants are classified according to
their light requirements.
◆ Know how to properly water and fertilize
indoor plants.
◆ Recognize symptoms of inadequate or
excessive light, relative humidity, fertility,
and water in indoor plants.
◆ Know the techniques of proper pruning,
grooming, cleaning, and repotting of indoor
plants.
◆ Know the major pests and disease on indoor
plants and how to troubleshoot common
problems.
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Indoor Plants
Introduction
Most ornamental plants grown indoors are tropical plants. Bear in mind that most home and office
environments are poorly suited to tropical plant
needs. Thus, the task of the house plant owner is to
select plants that can best withstand indoor conditions of a specific location.
Selecting An Indoor Plant
Select only foliage plants that appear to be free
of insects and diseases. Check the undersides of the
foliage and the axils of leaves for signs of insects or
diseases. Select plants that look sturdy, clean, wellpotted, and shapely.
Choose plants with healthy foliage. Avoid
those that have yellow or chlorotic leaves, brown
leaf margins, wilted or water-soaked foliage, spots or
blotches, or spindly growth. Also avoid plants with
torn leaves and those that have been treated with
“leaf shines,” which give leaves an unnatural polish.
Plants having new flowers and leaf buds along with
young growth are usually of superior quality.
Remember that it is easier to purchase a plant
that requires the same environmental conditions the
residence has to offer than to change the environment of the home or office to suit the plant.
Transporting Indoor Plants
When transporting plants, remember the two
seasons that can damage plants: hot summer and
cold winter. In the summer avoid placing plants
in a car and leaving the doors and windows closed,
because the temperature may rise so high that the
plant is destroyed in a short period of time. Even if
the air conditioner is on and it’s comfortable in the
car, the plant can be burned by the sun shining on
it for several hours. Shade the plant from direct sun
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while it is in the car.
During winter months, wrap plants thoroughly
before carrying them to the car. A short run from
the store to the car in very low temperatures can kill
or severely damage plants. Wrap plants thoroughly
with newspaper or paper bags, and place them in the
front of the car and turn on the heater. The trunk
of most cars is too cold to carry plants safely during
winter months.
On an extended trip, make special arrangements
so that plants will not be frozen or damaged by cold
weather. Many foliage plants will be damaged if the
temperature drops much below 50 oF, so keep them
as warm as possible when moving them from one
location to another.
Acclimatization
Research conducted in Florida in the late 1970s
revealed an interesting phenomenon. Tropical
plants grown in full sun have leaves called “sun
leaves” that are structurally different from the leaves
of plants grown in the shade or “shade leaves.” Sun
leaves have fewer chloroplasts, thus, less chlorophyll. Their chloroplasts are located deep inside the
leaves, and the leaves are thick, small, and numerous. Shade leaves have greater numbers of chloroplasts and thus more chlorophyll; they are thin,
large, and few in number.
When plants are grown in strong light, they
develop sun leaves that are very inefficient photosynthetically. If these same plants are placed in low
light, they must either remake existing sun leaves
or drop their sun leaves and grow a new set of shade
leaves that are photosynthetically more efficient. To
reduce the shock that occurs when a plant with sun
leaves is placed in shade, gradually reduce the light
levels it is exposed to. This process is called accli-
matization.
When placing plants outdoors in the summer, acclimatize
them by gradually increasing
light intensities. Reverse the
process before plants are brought
indoors in the fall. For newly
purchased plants, acclimatize
them by first locating them in a
high light (southern exposure)
area and gradually moving them
to their permanent darker location over a period of 4 to 8
weeks.
Environmental Needs
Light, water, temperature,
humidity, ventilation, fertilization, and soil are the chief
factors affecting plant growth.
Incorrect proportions of any one
will prevent a plant from growing properly indoors.
Light
Light is probably the most
essential factor for indoor plant
growth. The growth of plants
and the length of time they
remain active depend on the
amount of light they receive.
Plants need light as an energy source for photosynthesis.
When examining light levels
for house plants, consider three
aspects of light: intensity, duration, and quality.
Light intensity influences
the manufacture of plant food,
stem length, leaf color, and flowering. Indoor plants are often
classified by the amount of light
required for growth (Table 18.1):
Low Light—minimum of 75
to 200 footcandles (fc). Place
these plants in areas more than
8 ft. from windows such as the
center of a room, a hallway, or
an inside wall. Northern exposures often fall into this category,
even when close to the window.
Table 18.1
Light requirements in footcandles (fc) for some common indoor plants 1.
Low Light
(75-200 fc)
Aglaonema commutatum
Aglaonema commutatum cv. Silver King
Aglaonema modestum
Aspidistra elatior
Aspidistra elatior cv. Variegata
Epipremnum aureum
Epipremnum aureum cv. Marble Queen
Sansevieria trifasciata
Sansevieria trifasciata cv. Laurentii
Scindapsus aureus ‘Marble Queen’
Syngonium podophyllum Silver Evergreen
Silver King Evergreen
Chinese Evergreen
Cast-iron Plant
Variegated Cast-iron Plant
Golden Pothos
Marble Queen Pothos
Snake Plant
Goldband Sansevieria
Taro Vine
Goosefoot plant
Medium Light
(200-325 fc)
2
Aechmea fasciata Aphelandra squarrosa
Asparagus densiflorus cv. Myers
Asparagus densiflorus cv. Sprengeri
Asparagus setaceus
Beaucarnea recurvata
Begonia masoniana
Blechnum gibbum2
Chamaedorea elegans cv. Bella2
Chlorophytum comosum cv. Variegatum
Chrysalidocarpus lutescens
Cissus antarctica
Cissus rhombifolia
Dieffenbachia amoena
Dieffenbachia amoena cv. Tropic Snow
Dieffenbachia maculata
Dieffenbachia maculata cv. Rudolph Roehrs2
Dizygotheca elegantissima
Dracaena deremensis cv. Janet Craig2
Dracaena deremensis cv. Warneckii2
Dracaena fragrans cv. Massangeana2
Dracaena godseffiana2
Dracaena marginata2
Dracaena sanderana2
Fatsia japonica
Ficus benjamina
Ficus elastica cv. Decora
Ficus lyrata
Ficus retusa
Gynura aurantiaca
Howea forsteriana
Hoya carnosa
Silver Vase
Zebra Plant
Plume Asparagus
Sprengeri Asparagus
Fern Asparagus
Ponytail Palm
Iron Cross Begonia
Palm Fern
Bella Parlor Palm
Spider Plant
Areca palm
Kangaroo Vine
Grape Ivy
Giant Dumbcane
Tropic Snow Dumbcane
Spotted Dumbcane
Gold Dieffenbachia
False Aralia
Janet Craig Dracaena
Striped Dracaena
Corn Plant
Gold-dust Dracaena
Red-margined Dracaena
Ribbon Plant
Japanese Fatsia
Weeping Fig
India Rubber Plant
Fiddle-leaf Fig
Indian Laurel
Velvet Plant
Kentia Palm
Wax Plant
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Table 18.1 (continued)
Light requirements in footcandles (fc) for some common indoor plants.
Iresine lindeniiBloodleaf
Maranta leuconeura cv. Erythroneura2
Red-veined Prayer Plant
Monstera deliciosa
Split-leaf Philodendron
Nephrolepis exaltata cv. Bostoniensis
Boston Fern
Pandanus veitchii
Variegated Screw Pine
Peperomia caperata2
Emerald Ripple Peperomia
Peperomia obutusifolia
Oval-leaf Peperomia
Peperomia obtusifolia cv. Variegata2
Variegated Peperomia
2
Philodendron bipennifolium Fiddle-leaf Philodendron
Philodendron scandens subsp.oxycardium2 Heart-leaf Philodendron
Philodendron selloum
Tree Philodendron
2
Pilea cadierei Aluminum Plant
Pilea involucrata2
Friendship Plant
Plectranthus australis
Swedish Ivy
Polyscias balfouriana cv. Marginata
Variegated Balfour Aralia
Saintpaulia sp., hybrids, and cvs.
African Violet
Spathiphyllum cv. Clevelandi
Cleveland Peace Lily
Spathiphyllum cv. Mauna Loa
Mauna Loa Peace Lily
2
Tradescantia fluminensis Inch Plant
Zebrina pendula2
Wandering Jew
High Light
(>325 fc)
Aloe barbadensis
Aloe Vera
3
Araucaria bidwillii Monkey Puzzle Tree
Araucaria heterophylla2,3
Norfolk Island Pine
Bougainvillea glabra3
Paper Flower
Brassaia actinophylla
Schefflera
3
Caryota mitis Fishtail Palm
Chamaedorea erumpens2,3
Bamboo Plant
Chrysalidocarpus lutescens3
Areca Palm
Citrofortunella mitis
Calamondin Orange
Coffea arabicaCoffee
Cordyline terminalis
Ti Plant
Crassula argentea
Jade Plant
Cycas revoluta3
Sago Palm
x Fatshedera lizei3
Botanical Wonder
Ficus lyrata2,3
Fiddle leaf fig
Hibiscus rosa-sinensis
Chinese Hibiscus
Podocarpus gracilior
Weeping Podocarpus
Polyscias fruticosa
Ming Aralia
2
Rhoeo spathacea Moses-in-the-Cradle
Schlumbergera cv. Bridgesii
Christmas Cactus
Sedum morganianum
Burro’s Tail
Solenostemon scutellariodesColeus
Research has shown that just to maintain the appearance of foliage plants for one year,
they require about 85 fc for 12 hours per day. At least 200 fc are necessary for foliage
plants to show any benefit from fertilization.
2
May also be conditioned to grow in low light.
3
May also be conditioned to grow in medium light.
1
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Many locations that receive
only artificial light are also low
light situations.
Medium Light—minimum
of 200 to 325 fc. Use in locations 4 to 8 ft. from south and
east windows and west windows
that do not receive direct sun.
High Light—more than 325
fc. These plants thrive in areas
within 4 ft. of large south-, east-,
and west-facing windows.
It is important to match
plants with locations that satisfy
their basic light requirements.
Plants grown in correct light
conditions are vigorous, compact, and highly branched. Color is vibrant, leaves are normal
size, and stems are sturdy. Plants
grown at a light intensity below
their optimum will have smaller
leaves and less vivid color.
They often grow more open and
leggy and pruning may be necessary to encourage a compact
form. These plants should be
kept drier than those in bright
light and fertilized less often. A
plant that receives significantly
less than its required amount
of light may survive for several
months to a year, while gradually deteriorating in appearance
and vigor.
When light levels are too
high, plants leaves show an
overall yellowing that results
from the destruction of chlorophyll. Eventually large brown
spots of dead tissue may develop. This is often referred to as
leaf scorch or leaf burn.
Many reference books provide interiorscape professionals and home gardeners with
information on the light levels
necessary to maintain plants
indoors. A wide variety of light
meters are available for measuring light intensities in indoor
Table 18.2
Approximate footcandle readings using a
camera to estimate light intensities.
f-stop
f/2
f/2.8
f/4
f/5.6
f/8
f/11
f/16
Approximate Footcandles
40
75
150
300
600
1,200
2,400
Table 18.3
Average light intensity in foot candles (fc) for
various lighting situations. (from G. L. Wade,
2004).
Sunny day
Cloudy day
Conference room
Reading at home
Retail stores
Church chapels
10,000 fc
500-2,000 fc
20-30 fc
20-30 fc
30-100 fc
5-10 fc
sunlight levels indoors. These include the color of
interior walls and floors, types of window coverings,
roof overhangs, outside awnings, and nearby buildings and trees that filter or block incoming light.
Day length or duration of light received by
plants is also of some importance but generally only
for house plants that are photosensitive. Poinsettia will bud and flower only when the day length is
short (10 hours of daylight); kalanchoe and Christmas cactus require 11 hours of daylight or less. Most
flowering indoor plants are indifferent to day length.
Low light intensity can be compensated by
increasing the time or duration that the plant is exposed to light, as long as the plant is not sensitive to
day length in its flowering response. Increased hours
of lighting allow the plant to make sufficient food
to survive and grow. However, plants require some
period of darkness to develop properly and thus
should be illuminated for no more than 16 hours.
environments. They can eliminate much of the
guesswork in selecting plants that are adapted to
light levels in a given location.
Light intensity is measured in footcandles. One
footcandle is the amount of light cast on a white surface by one candle, 1 foot away, in an otherwise dark
room. You can get a rough measurement of footcandles with a camera equipped with a built-in light
meter. Set the film-speed dial to ASA 25 and the
shutter speed to 1/60 second. Place a piece of opaque
white paper where you wish to determine the light
intensity. Aim the camera toward the paper, close
enough that the paper fills the entire field of view.
Finally, adjust the f-stop or lens opening until the
built-in meter indicates a correct exposure. Read
the approximate light intensity from the Table 18.2.
The intensity and duration of natural sunlight
that reaches indoor locations varies throughout the
year (Figure 18.1). In winter,
days are shorter and the sun’s
Figure 18.1
path is lower and farther to the
As with day length, the sun’s path across the horizon changes with the
south. Therefore, most plants
seasons. The sun is much higher above the horizon in the summer than
will receive fewer hours of less
during the winter.
intense sunlight from a more
southerly angle in the winter.
However, plants growing close to
an unshaded south-facing window may receive more direct sunlight at this time of year because
of the low sun angle. In summer
the days are longer and the sun’s
path is higher above the horizon.
For many plants this is the peak
growing period. Table 18.3 lists
average light intensities in different lighting situations.
Keep in mind that there are
less obvious factors that affect
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Excessive light can be harmful as too little light.
When a plant gets too much direct light, the leaves
become pale, sometimes sunburn, turn brown, and
die. Therefore, during the summer months, protect
plants from too much direct sunlight.
If artificial lights are to be used as the only
source of light for growing plants, the quality of
light or wavelength must be considered. For photosynthesis, plants require mostly blues and reds,
which can be inexpensively met with cool white
fluorescent lights. (Note: There is little difference
between warm white and cool white tubes except
for cost; warm white tubes are more expensive.)
Incandescent lights produce a great deal of heat and
are not very efficient users of electricity. Typically, a
fixture holding two 40-watt tubes is positioned about
12 inches above the plants. Most plants need 12 to
16 hours of artificial light per day for good growth.
Serious indoor gardeners should consider high
intensity discharge lights, such as metal halide and
high-pressure sodium bulbs. Both halide and sodium
bulbs produce light spectrums that are acceptable to
most plants. However, halide bulbs produce light
that is slightly closer to sunlight than sodium bulbs.
Sodiums produce little blue-violet light, which can
cause some plants to develop long internodes or
become leggy. Also, sodium bulbs produce light
that appears slightly yellowish to the eye, so plants
don’t appear quite as natural under it. Consider this
factor if the light will be used in a living area where
the plants are supposed to look as attractive as possible. Choose sodium lights if you’re not interested
in showcasing the indoor plants; they are much
more cost-efficient to run than halides when considering initial cost, lifetime of the bulb, and energy
efficiency.
Boost the brightness of artificial lights by using
white or silver reflective material under the plant
and on the walls of the growing area to reflect light
back onto the plants. This sends more light to the
plants and provides more light from different angles
to help the plants grow into a more natural shape.
Water
One common cause of indoor plant death is improper watering. A common question from gardeners is, “How often should I water my plants?” There
is no pat answer to this question. The amount and
frequency of watering depends on the following
variables:
Potting Mixtures – Different soil mixes require
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different watering schedules. Heavy fine-textured
potting media and those that contain a lot of peat
moss hold more moisture than loose, porous mixtures of bark, sand, and perlite.
Pot – Water evaporates rapidly from the sides of
an untreated porous clay pot, which requires more
frequent watering than plants growing in nonporous
glazed or plastic pots.
Plants – There is a wide range of watering requirements for different species of plants. Plants
with large or very thin leaves and those with fine
surface roots usually require more frequent watering
than succulent plants with fleshy leaves and stems
that are able to store water internally.
Plant Size – A large plant in a small pot will
need water more often than a small plant in a large
pot. Also, a plant with a lot of leaves will need
more frequent watering than one with a few leaves.
Location – In a warm, dry, sunny location,
plants need more frequent watering than they do in
cool, low-light situations.
Growth Stage – When a plant is dormant (not
actively growing), it will need less water.
The rule-of-thumb in watering is to water when
necessary. The following methods may be used to
determine when to water:
Touch – The most accurate gauge is to water
when the potting mixture feels dry to the touch.
Stick your finger into the mix up to the first joint; if
it is dry at your finger tip, you need to water.
Tap the pot – When the potting mix in a clay
pot begins to dry, it shrinks away from the sides of
the pot. Rap the side of the pot with the knuckles
or a stick. If the sound is dull, the soil is moist; if
hollow, water is needed.
Estimate Weight – As potting mixtures become
dry, a definite loss in weight can be observed.
Judge Soil Color – Potting mixtures will change
from a dark to light color as they dry.
When watering is required, water thoroughly.
Apply enough water until it runs out of the bottom
of the pot. This washes out the excess salts, and it
guarantees that the bottom two-thirds of the pot,
which contains most of the roots, will receive sufficient water. However, don’t let the pot sit in the
water that runs out. Empty the drip saucer.
Temperature
Most indoor plants grow well under normal
temperatures found in homes and offices. The ideal
temperature is 70 to 80 oF during the day and 60 to
70 oF at night. The lower night temperature induces
physiological recovery from moisture loss, intensifies
flower color, and prolongs flower life. Excessively
low or high temperatures may cause plant failures,
stop growth, or create a spindly appearance and leaf
injury or drop. A cooler temperature at night is
actually more desirable for plant growth than higher
temperatures. A good rule-of-thumb is to keep the
night temperature 10 to 15 degrees lower than the
day temperature.
Since most indoor plants are tropical in origin,
few tolerate freezing temperatures. In fact, some
house plants are damaged by temperatures slightly
above freezing (50 to 55 oF), a phenomenon called
chilling injury. Dieffenbachia, Aglaonema, Spathiphyllum, and Dracaena are very sensitive to chilling
temperatures. Injury often occurs in winter when
the plants are located close to windows or when
homeowners go away for a few days and turn their
thermostats down to conserve heat. Injury varies
with the temperature and length of exposure.
Cold water can also injure some plants, notably
the gesneriads. A difference as little as 15 oF in leaf
and water temperature can cause leaf damage in
African violet, known as ring spot disorder. These
symptoms are often incorrectly diagnosed as viral or
nutritional disorders. Avoid the problem by keeping
water off the foliage.
Humidity
Atmospheric humidity is expressed as a percentage of the moisture saturation of air. In a moderate
humidity range of 20 to 40%, it is possible to grow
a variety of flowering and foliage plants; cactus and
other succulents do well in a humidity range of 5 to
15%. In dry air, especially during the winter months
when heating systems are operating, plants will often lose water from leaf tissues at a faster rate than
can be absorbed through the root system. When
this occurs, leaf tips become brown, and flowering
plants may lose flower buds.
Contrary to popular opinion, placing indoor
plants on a pebble-filled tray of water will not sufficiently increase humidity levels, according to
research findings. To increase humidity levels up
to 50% indoors, you can place the tray and pot in a
container such as an aquarium tank with an adjustable opening at the top. Water evaporation from
the tray leading to increased humidity levels in the
tank can be accelerated by placing the tray on a
heating cable. If you choose to use an aquarium,
Soluble Salt Buildup
Reduced growth, brown leaf tips, dropping
of lower leaves, small new growth, dead root
tips, and wilting are all signs of high soluble
salts. These salts will accumulate on top of
the soil, forming a yellow to white crust. A
ring of salt deposits may be formed around
the pot at the soil line or around the drainage
hole. Salts will also build up on the outside of
clay pots.
Soluble salts are minerals dissolved in water. Fertilizer dissolved in water becomes a
soluble salt. When water evaporates from
the soil, the minerals or salts stay behind. As
the salts in the soil become more and more
concentrated, plants find it harder and harder
to take up water. If salts build up to an extremely high level, water can be taken out of
the root tips, causing them to die.
High soluble salts damage the roots directly,
and because the plant is weakened, it is
more susceptible to attack from insects and
diseases. One of the most common problems associated with high salt levels is root
rot.
The best way to prevent soluble salt injury
is to stop the salts from building up. Water
correctly. Whether you apply water from
the top or from the bottom with a saucer or
tray, leach the soil at every watering or at
least once a month. Leaching is done by
watering the soil thoroughly, allowing the
excess to flow out the bottom drain holes of
the container. If a layer of salts has formed a
crust on top of the soil, you should remove
the salt crust before you begin to leach. Do
not remove more than 1 inch of soil. If the
soluble salt level is extremely high, if the pot
is coated with white salt residue, or if the pot
has no drainage, repot the plant into a clean
install a fan to improve air circulation and air movement. Another way of increasing humidity levels
that will offer comfort to you as well during the winter months is a room humidifier. Purchase a digital
hygrometer which measures relative humidity and
use it to observe indoor humidity levels.
Ventilation
Good air circulation is necessary to the wellbeing of plants. However, plants should be placed
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in draft-free locations. Areas where cross-currents
of air occur are not considered good for plants.
Fertilization
Indoor plants, like most others, need fertilizers
containing the three major plant nutrients: nitrogen, phosphorus, and potassium. These are available in many different combinations and under a
multitude of brand names. Each brand should be
analyzed by looking at the label. The analysis is
printed on the label and indicates the percent by
weight of each nutrient in the formulation. Most
indoor plants grow vigorously with a 1-1-1 ratio
such as a 20-20-20 fertilizer. Just a reminder: the
first number represents nitrogen (N), the second
phosphorus (P2O5 or available phosphoric acid, and
the third potassium (K2O, available or soluble potash). However, you may want to increase the ratio
of nitrogen for a nonflowering plant, such as foliage
plants (for example, Dieffenbachia and Ficus). Liquid fertilizers are convenient for indoor gardeners.
Water-soluble granular, pill, and slow-release forms
are also effective. Regardless of the analysis and formulation, always follow the manufacturer’s labelled
instructions.
Observation will guide you in determining
a plant’s fertilizer needs. As a rule, applications
should be more frequent when the plants are in a
growth stage. This is usually in the spring and summer when sunlight intensity increases and the warm
days are longer. During the short days of winter,
many indoor plants that receive little or no artificial
light enter a resting stage. If plants go into a winter
rest period, it’s best to give them little, if any, fertilizer. Plants that have just been transplanted or repotted will obtain sufficient nutrients from the fresh
potting soil for at least 4 to 8 weeks. They do not
require supplemental fertilizer during this time.
Potting Medium
The success or failure of growing plants in containers depends to a large extent on the potting mixture. There is no one potting mix that is infinitely
better than any other. A good quality container mix
has the following general requirements:
• Dense enough to support the plant
• Good nutrient-holding capacity
• Allows water and air to pass through readily, yet retains some moisture
• Free of pathogens and weed seeds.
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dia for plants grown in containers. These soils need
to be amended with pine bark, perlite, vermiculite,
or sand to improve their physical structure and water- and nutrient-retention capacities. Also, native
soil should be sterilized to kill disease organisms and
weed seed. Spread moist soil in a tray or pan and
bake at 180 oF for 30 minutes.
Many indoor gardeners find it more convenient
to use commercially prepared mixes, termed “artificial” or “soilless” mixes when they do not contain
soil. They vary in price, ingredients, and physical
and chemical characteristics. You may have to try
several before you find one that gives good results
under your conditions and meets all the requirements of a good container mix. Professionally
evaluated mixes contain coarse sand, processed bark,
sphagnum peat moss, perlite, vermiculite, leaf mold,
and other ingredients.
You can prepare your own artificial potting medium with little difficulty. Most mixes contain one
or more of the following materials:
Peat moss is readily available baled or bagged.
Sphagnum peat moss is recommended. Michigan
peat, peat humus, and native peat are usually too
decomposed to provide necessary structural and
water drainage characteristics. Most sphagnum peat
moss is acid, with a pH between 3 and 4; therefore,
it is recommended that about 20 lb. of finely ground
limestone be added per cubic yard of peat moss to
raise the medium pH to approximately 6, an ideal
pH for foliage plants. It is lightweight and may hold
as much as 60% of its weight in water. While it has
little nutritional value, peat moss is capable of retaining added nutrients quite well.
Vermiculite is a sterile, lightweight, mica product. When mica is heated to about 1,400 oF, it expands its platelike structure. Vermiculite will hold
large quantities of air, water, and nutrients needed
for plant growth. Its pH is between 5 and 7.2, and
it contains calcium (Ca), magnesium (Mg), and potassium (K). It is lightweight and has a high waterholding capacity, yet it provides excellent drainage,
aeration, and can even increase the cation exchange
capacity of the medium. Unfortunately, its structure
does not hold up over time. It seems more suited
for short-term use (for example, in a germinating
or propagation medium). Vermiculite is marketed
in various particle sizes, with the 2 or 3 particle size
more commonly used for horticultural purposes.
Perlite is a sterile, lightweight, white, porous
product produced from the crushing and heating of
volcanic rock to about 1800 oF. Its principal value
in potting mixes is aeration. It does not hold water
and nutrients as well as vermiculite. The pH is usually between 7.0 and 7.5, but its pH does not influence the pH of the growing medium. Perlite can
cause fluoride burn on some foliage plants. Fluoride
damage is usually seen on the tips of the leaves.
The burn progresses from the tip down into the
leaf. Many fluoride-sensitive plants are members of
the Liliaceae family: Dracaena spp., Pleomele spp.,
Cordyline spp., Chlorophytum spp.; however, some
plants in the Agavaceae, Araceae, Marantaceae, and
Palmae families may also develop fluoride injury.
Sand of the coarse concrete grade is commonly
used for propagation purposes to ensure drainage and
aeration during rooting. It will impart these same
benefits to the growing medium. Sand adds weight
to the mix and has no cation exchange capacity.
Pine bark is readily available and relatively
inexpensive (less than or equal to half of imported
peat); therefore, many view it as a substitute for peat
moss. The bark is cured (after being composted)
for at least 3 months before it is screened, usually
into three particle sizes. The finest size (less than
or equal to 3/8 inch), often referred to as the “soil
conditioning grade,” is excellent for incorporating into a potting medium for foliage plants. Its
nutrient-holding capacity is strong following curing,
and it decomposes slowly. If properly fertilized and
watered, some plants do well in pine bark alone.
Two soilless mixes were developed at Cornell
University to help commercial growers, but they are
easily adaptable to home use. Each recipe will each
make one bushel of mix (Table 18.4).
Soil Mixes for Specific Plants
Soils must have the most efficient combination of elements for the type of plant to be grown in
them. According to generally accepted standards,
we can divide house plant soils into four distinct
groups, according to the type of plant they are most
suited for.
Foliage plants – This soil should be moderately
rich, have a good base of clay loam, and hold moisture and nutrients adequately. It must be a crumbly,
well-textured soil. It is generally made up of one
part of good garden loam (or packaged potting soil);
one part of clean sand or perlite; and one-half to
one part of either peat moss, compost, or vermiculite. Mix about 1 teaspoon of superphosphate with
each quart of mixed potting soil to encourage good
Table 18.4
Soil mix recipes.
Cornell Foliage Plant Mix:
1
/2 bu sphagnum peat moss
1
/4 bu vermiculite, No. 2
1
/4 bu perlite (medium fine)
8 tbsp ground dolomitic lime
2 tbsp superphosphate (20% powdered)
3 tbsp 10-10-10 fertilizer
1 tbsp iron sulfate
1 tbsp potassium nitrate
This foliage plant mix is well-suited for ferns, Begonia, Cissus, Coleus, Ficus, Maranta, Pelargonium,
Pilea, Sansevieria.
Cornell Epiphytic Mix:
1
/3 bu Douglas fir bark (finely ground)
1
/3 bu sphagnum peat moss (shredded)
1
/3 bu perlite (medium fine)
8 tbsp ground dolomitic lime
6 tbsp superphosphate (20% powdered)
3 tbsp 10-10-10 fertilizer
1 tbsp iron sulfate
1 tbsp potassium nitrate
This plant mix is suitable for bromeliads, cacti,
Crassula, Dieffenbachia, Episcia, Gloxinia, Hoya,
Monstera, Philodendron, and Peperomia.
A supplemental application of a water-soluble fertilizer such as a 20-20-20 with trace or minor elements should be given on a monthly basis while the
plants are actively growing.
root growth after repotting. If the garden soil is alkaline, sphagnum peat moss will have enough of an
acid reaction to neutralize the mixture. This soil is
used for all foliage plants and some flowering plants
that do not prefer a rich soil.
Flowering indoor plants – This soil is often
referred to as “humus soil” because it contains about
50% humus-rich materials or similar ingredients. It
is important that the soil does not become so rich
that it remains soggy long after watering. Add two
parts of sphagnum, or one part sphagnum and one
part vermiculite, to one part garden loam (or sterilized commercially available potting soil) and one
part clean sand. Also add 1 teaspoon of superphosphate per quart of soil mixture. This soil is generally
used for African violets, gloxinias, begonias, calla
lilies, and other tropical flowering plants.
Cacti and succulents – This soil does not need
any humus material. It is composed of equal parts
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of sand, garden soil, and vermiculite or perlite. It is
preferred for cacti and other fleshy-leaved, deserttype succulents.
Orchids – Fir tree bark or Osmunda fiber (made
from the roots of the cinnamon fern, Osmunda cinnamomea) is generally used in glazed or plastic pots.
The container should be large enough so that new
growth is 1 to 2 inches from the rim. Broken clay
pieces can be placed 1-inch deep on the bottom of
the container.
Any soil containing garden loam should be pasteurized. This can be done easily at home. Spread
the soil on a cookie tray and bake at 180 oF for 30
minutes. Do not heat it longer than 30 minutes,
and be aware that it will smell unpleasant while
baking.
Containers
Many types of containers can be used for growing plants. A good container should be large
enough to provide room for soil and roots, have sufficient headroom for proper watering, provide bottom drainage, and be attractive without competing
with the plant it holds. Containers may ceramic,
plastic, fiberglass, wood, aluminum, copper, brass,
and many other materials.
Clay and Ceramic
Unglazed and glazed, porous clay pots with
drainage holes are widely used. Unglazed clay
pots absorb and lose moisture through their walls,
and therefore require more frequent watering than
plastic, glass, metal, wood, or glazed pots. For that
reason, most amateurs who have a tendency to overwater are usually more successful with clay pots.
Although easily broken, clay pots provide excellent
aeration for plant roots and are considered by some
to be the healthiest type of container for a plant.
Ceramic pots are usually glazed on the outside,
sometimes also on the inside. They are frequently
designed without drainage holes. Containers without drainage holes should be “double-potted.” Pot
the plant in a container that has a drainage hole and
is 1 inch less in diameter and shorter than the container without drainage (decorative pot). Place several inches of gravel in the bottom of the decorative
pot and place the potted plant on the gravel layer.
Plastic and Fiberglass
Plastic and fiberglass containers are usually quite
light and easy to handle. They have become popuIndoor Plants
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lar because they are relatively inexpensive and attractive in shape and color. Plastic pots are easy to
sterilize or clean for reuse; and because they are not
porous, they need less frequent watering and tend to
accumulate fewer salts.
Repotting
Actively growing house plants need repotting
from time to time. This occurs very rarely with
some slow-growing plants, more frequently with
others. Foliage plants require repotting when their
roots have filled the pot and are growing out the
bottom.
When repotting becomes necessary, it should
be done without delay. Select a pot that is one size
larger or no more than 2 inches larger in diameter
than the original pot. The pot should have at least
one drainage hole and must be clean. Wash soluble
salts from pots with water and a scrub brush and
wash all pots in a solution of 1 part liquid bleach to
9 parts water.
Most plants are removed easily from their pot
if the lip of the container is knocked upside down
against any solid object. Hold your hand over the
soil, straddling the plant between the fore- and middle fingers, holding back the soil, and then gently
knocking the root ball out of its present container.
If the plant has become root-bound with roots growing around the root ball, cut and unwind the encircling roots; otherwise, the roots will never develop
normally. If the old soil surface has accumulated
salts, remove the top inch.
To repot, place a small piece of a broken clay
pot over the drainage hole to prevent soil from
draining through the hole. Then cover the bottom of the pot with a layer of potting mix and firm
it with your fingers. This layer of mix should leave
about 1 inch of headroom—the amount of space
between the soil level and the top of the pot that
allows for watering. Fill around the sides between
the root ball and the pot. Do not add soil above the
original level on the root ball, unless the roots are
exposed or if some of the surface soil was removed.
Do not pack the soil to firm or settle it; tap the pot
against a table top or gently press the soil with your
fingers. Water thoroughly to settle the soil.
Training and Grooming
To look their best, indoor plants occasionally
need some extra attention. This doesn’t require
much time and is often enjoyable. Pinching, for ex-
ample, is the removal of an inch or less of new stem
and leaf growth (Figure 18.2). When necessary,
pinch to just above a node. This stimulates shoot
growth below the pinch. Pinching can be a onetime
or an ongoing activity, depending on the needs and
desires of the plant owner. If a plant should be kept
compact but well filled out, frequent pinching will
achieve this goal.
Pruning involves the removal of shoots. Sometimes an entire branch or section of a plant should
be removed for the sake of appearance or health
reasons, such as the removal of insect-infested or
diseased shoots.
Disbudding is the removal of certain flower buds
either to obtain larger blooms from a few choice
buds or to prevent flowering in a very young plant or
recently rooted cutting.
Finally, it is important to keep plants clean and
neat. It not only improves their appearance but
also reduces the incidence of insects and disease
problems. Remove all spent flowers, dying leaves,
and dead branches. Plants with hairy leaves, such
as African violets, gloxinias, and tuberous begonias
should not be wet, while the foliage of most others can be cleaned with a moist, soft cloth. If the
tips of leaves become brown and dry, trim them off
neatly with sharp scissors. Plant leaf-shine materials
should be avoided; they attract dust and can slow
plant growth. Turn plants regularly if possible to
expose all sides to light coming from one direction;
this encourages a more uniform shape.
Diagnosing Indoor Plant Problems
Indoor plants are subject to a wide variety of ailments and abuses. It is often impossible to diagnose
the cause of a particular problem unless you keep an
accurate record of environmental conditions and
changes, fertilizer history, pesticide application, and
other factors. Few homeowners keep such records
and diagnosis often hinges on visual symptoms. The
situation is complicated by the fact that various
disorders may produce essentially the same visual
symptoms. Thus, it is not always possible to isolate
the exact cause of a given problem. Nevertheless,
there are certain symptoms that often point to specific causes (see Tables 18.5 and 18.6).
Insects and Mites
Only a relatively small group of insects and
few diseases harm indoor plants. However, insect
infestations can reach extremely large populations
in a short time because there are no biological or
mechanical controls in this controlled environment.
The few insects that can infest indoor plants are,
therefore, potentially devastating, especially if infestations are not controlled early.
Mealybugs are soft-bodied insects covered with
a white, powdery material. When mature, they vary
from 1/5 to 1/3 inch in length, and some species have
long waxy filaments extending from the rear of the
body. They damage plants by sucking plant juices.
Spider mites are about 1/50 inch long when mature, and may be greenish, yellowish, reddish or virtually colorless. They are commonly found on the
undersides of the leaves. When plants are heavily
infested, fine webbing will be noticed. Mites suck
juices from plants through their needlelike mouthparts. A 10- or 15X magnifying glass is very helpful
in detecting infestations before severe damage occurs. You can also shake a leaf over a piece of white
paper and look for moving specks.
Aphids may be green, pink, black, brown, yellow, or blue in color. They vary from 1/25 to 1/8 inch
Figure 18.2
Pinching
Leggy plant needs to grow bushier
for a more compact form.
Pinch out growing tip of tallest stem,
removing it close to leaf point.
New growth forms just below pinchedout tip and makes plant bushy.
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Table 18.5
Diagnosing symptoms of common indoor plant problems.
Symptoms
Foliage: Growth: Flowers:
tips or margins brown weak, thin and soft fail to develop--buds drop
bend down and curl new leaves small color is less intense
yellowish green none develop decline too fast
oldest drop plant died become smaller
all drop spots
no blooms
Possible Causes:
wilt
Excess Light: i.e., exposure to direct
sun can be too intense for many
plants.
Insufficient Light: impairs
photosynthesis and flowering.
Day Length: if too short, reduces
growth, flowering and lifeexpectancy.
High Temperature: especially at
night reduces growth, vigor, and
flowering.
Low Temperature: continued
exposure is harmful to plant growth.
Lack of Water: limiting factor for
growth and survival.
Overwatering or Poor Drainage:
reduces soil-aeration--roots die, water
and nutrients are not absorbed.
Too Much Fertilizer: accumulation
of soluble salts injures plant roots,
reduces water uptake.
Lack of Fertilizer: causes a deficiency
of nutrients required for plant growth.
Compacted Soil: reduces root
functions and activity.
Growing Container: too small or
too large in relation to plant size.
Low Humidity: air too dry to maintain healthy growth and flowering.
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Table 18.6
Trouble-shooting table of common houseplant problems.
Symptoms
Plant wilting
Leaf yellowing, foliage fades,
yellows browns or wilts
Possible Causes
Controls/Comments
Overwatering or lack of water: overwatering can cause root rots. Healthy roots
should be light colored and firm.
Use a well drained, peat-based
potting media. Severely damaged
plants should be discarded.
Various root rots: pull plant out of the pot
and observe roots for discoloration. Diseased
roots will appear dark and soft.
Remove diseased plants from
their pots, cut out infested
portions (rotten), and replant
remaining healthy sections. Take
cuttings and root them in sterile
potting mix.
Stem cankers: discolored areas on stem.
Prune out affected areas.
Aphids: small soft bodied insects found on
leaves, stems and flower buds.
Regularly rinse plants with water
to keep down pest problems. Use
a registered houseplant spray to
control pests. Plants damaged by
heavy insect or mite feeding can
be injured by insecticidal sprays.
Severely damaged plants should
be discarded. Remove diseased
plants from their pots, cut out
portions (rotten), and replant
remaining healthy sections. Take
cuttings and root them in sterile
potting mix.
Spider mites: minute pests that feed on lower
leaf surfaces, webbing may be visible.
Mealybugs: white cottony insects.
Whiteflies: adults are tiny white insects that
fly from the plants when disturbed. Immature
stages found on lower leaf surfaces.
Brown soft scale and hemispherical scale:
raised black or brown bumps on leaves and
stems.
Root rots: discolored and softened roots.
High soluble salts
Leach soil at least three times
with pot volume of fresh water
Bleached or whitened
leaves
Excessive light or sunburn
Acclimate plants slowly to higher
light intensities.
Fine stippling
Spider mites: minute pests that feed on
lower leaf surfaces, webbing may be
visible.
Regularly rinse plants with
water to keep down spider mite
problems. Use a registered
houseplant spray to control
mites. Plants damaged by heavy
mite feeding can be injured by
insecticidal sprays. Severely
damaged plants should be
discarded.
Reprinted from “IPM Series: Houseplants,” David L. Clement and Mary Kay Malinoski, Home and Garden Mimeo #HG60, Home
and Garden Information Center, Cooperative Extension Service, University of Maryland, College Park
(http://www.hgic.umd.edu/_media/documents/IPMSeriesHouseplantspfv.pdf).
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Table 18.6 (continued)
Symptoms
Possible Causes
Controls/Comments
Leaf spots and leaf blotches
Water spots, sunburn, various fungi,
bacteria.
Remove spotted leaves and
improve air circulation for leaf
diseases.
Leaf or shoot blackening
Cold Injury: symptoms may continue for
up to a week after exposure.
Protect plants from temperatures
Leaf scorch
Abiotic stresses such as over-fertilization,
high soluble salts, lack of water:
scorching symptoms can occur along leaf
margins or between veins.
Leach excessive fertilizer from
potting mix by flushing with water
or repot with fresh potting media.
Stunted, twisted and
distorted plant growth
Aphids: small soft bodied sucking insects.
Aphids can be controlled with
a stream of water or with a
registered insecticide. Cyclamen
mite infested plants and virus
infected plants cannot be cured
and should be discarded.
Cyclamen mites: predominately a pest of
flowering plants. New growth is affected
first.
below 50 °F.
Viruses: foliage appears mottled green and
yellow. Plants may be stunted.
Leaf mottling
Viruses: foliage appears mottled green and
yellow. Plants may be stunted.
White powdery coating
on leaves
Powdery mildew fungi: grows on the leaf
surface.
Fuzzy gray growth on
leaves or flowers
Discard infected plants
Provide better air circulation and
pick off infected leaves. Spray
with a registered fungicide if
disease is severe. Check horticultural oil labels for powdery
mildew control listings.
Grey mold: frequently infects old faded
flowers or older, lower foliage.
Provide better air circulation.
Pick off infected flowers or
leaves. Remove old blooms or
foliage.
Fluffy white wax
Mealybugs: white cottony insects may
occur on foliage, in leaf axles, leaf
sheaths, roots and bud scales.
Use a registered houseplant spray
to control mealybugs or use a
cotton swab dipped in alcohol to
kill individual mealybugs.
Leaves eaten or chewed
Check plants that have been outside
for the summer for pests such as
caterpillars, leaf feeding beetles, weevils,
grasshoppers, crickets, slugs, and earwigs.
Hand-pick pests and repot plants
before moving plants inside.
Few or no flowers
Low light levels, excessive fertilizer,
cyclamen mites.
Increase light levels by relocating
plants closer to a light source
or add additional artificial light
sources. Cyclamen mite infested
plants should be discarded.
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Table 18.6 (continued)
Symptoms
Spindly growth
Possible Causes
Low light levels or excessive fertilizer,
(high soluble salts)
Controls/Comments
Increase light levels by relocating
plants closer to a light source or add
additional artificial light sources.
Reduce fertilizer applications during
winter. Irrigate from the top of the
pot to leach out excess fertilizer
salts.
Poor growth
Poor culture, insects and diseases
Flying insects
Whiteflies: tiny white insects flying
around plants.
Use a registered insecticide for
whiteflies.
Fungus gnats: tiny black flies flying near
plants or near light sources.
Allow potting media to dry between
waterings.
Ants, sowbugs, springtails earwigs,
millipedes, slugs, slugs: often brought in
from outside when relocating plants from
outdoors.
Repot plants with fresh potting
media. Beneficial nematodes may
be used to control fungus gnat
larvae.
Insects in potting media
in length and may or may not have wings. They
are pear-shaped, have long antennae, and two short
cornicles or tubes extending from the rear end of
the body. Aphids suck plant juices and cause new
growth to curl and become distorted.
Scales can be almost any color depending on
the species. They are 1/8 to 1/3 inch long when mature and are surrounded with a waxy covering that
may be circular, oval, oblong, or pear-shaped. Scales
are found on both sides of the leaves as well as on
twigs and branches. They may be almost hidden in
the crevices of stems or leaf axils. Scales cause damage by sucking plant juices.
Whitefly adults are about 1/16 inch long, white
in color, and resemble tiny moths. When disturbed
they will swarm about the plant like a cloud. The
nymphs are 1/16 inch in length, pale green in color,
and flat and oval in shape. They are found on the
undersides of the leaves and cause damage by sucking plant juices.
Fungus gnat maggots, springtails and psocids are
soil pests that may damage the root systems of indoor plants. Fungus gnat maggots are white, wormlike in shape, and about 1/4 inch long when mature.
Springtails range in size from microscopic to about
1
/5 inch long, are usually white in color, and jump
when disturbed. Psocids range in size from about
1
/32 to 1/16 inch in length, are usually white- to graycolored, and may or may not have wings.
Controlling Insects
Carefully examine any newly purchased plants
or plants that have been summered outdoors to be
sure they are free of pests. After bringing a plant
home, isolate it for at least a month before placing it
with other plants.
Always use sterilized soil for potting to help
prevent infestations of soil pests, such as nematodes,
springtails, psocids, and fungus gnats.
Spraying plants with a forceful stream of room
temperature water every 2 weeks will remove many
insects before they have a chance to become established. This procedure is best done outdoors, in a
laundry sink, or in the bath tub. Spray the lower
surfaces of the leaves where most plant pests are
found. Spraying also keeps the foliage dust-free and
the plants looking attractive.
Washing with soapy water and a soft cloth may
be all that is needed to remove aphids, mealybugs,
and scale insects from broad-leaved plants. Use 2
teaspoons of a mild detergent to 1 gallon of water.
If one or a few plants are involved, you may be
able to control aphids and mealybugs by removing
them with a toothpick or tweezers. Caterpillars
may be picked off plants by hand and destroyed.
Cutworms, slugs, and snails may be found in their
hiding places during the daytime and destroyed or
picked from the plants at night when they come out
to feed.
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An easy way to control a light infestation of
mealybugs or aphids is to wet or remove the insects
with a cotton-tipped swab that has been dipped in
alcohol. Be careful not to overapply, because alcohol may burn the foliage.
For severe infestations or where large numbers
of plants are involved, chemical control may be
needed. For recommendations on selection and application of insecticides and miticides, contact the
Clemson Extension Home & Garden Information
Center.
Diseases
Plants grown indoors are troubled with few
plant diseases. This can be partly due to low humidity levels in the home. Most plant diseases spread
by spores, which require moisture for growth. Many
problems commonly attributed to diseases are the
result of unfavorable growing conditions. Overwatering is the primary cause of root and stem rot.
Excessive watering causes an oxygen deficiency in
the soil, resulting in root death and subsequent rot.
Often soilborne fungi and bacteria will invade root
systems that are weakened by an oxygen deficiency.
Root rots can be prevented by using sterile, porous
potting media, containers with adequate drainage
holes, and proper watering. When root rot occurs,
the top portion of the plant may be saved by airlayering or by taking cuttings.
Care of Special Potted Plants
Too little light, excessive heat, and improper
watering are the usual causes of failure in caring for
gift plants. These plants are grown in a greenhouse
where the night temperatures are usually cool, there
is ample light, and the air is moist. When they are
brought into a dry home where the light is poor and
the temperatures are maintained for human comfort,
results are frequently disappointing. Do not expect
to keep a gift plant from year to year. Enjoy them
while they are attractive and in season and then
discard.
Gardeners frequently ask whether they can carry
their poinsettias over to bloom again next year. It
is questionable whether the results are worth the
effort, as the quality of homegrown plants seldom
equals that of commercially grown greenhouse
plants.
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African Violet (Saintpaulia spp.) – African
violets are excellent indoor flowering plants. Available in many flower colors, they produce flowers
year-round under the proper growing conditions.
Individual flower clusters may last 3 to 6 weeks under good conditions. Poor flowering is often related
to insufficient light. East- and west-facing window
sills are the best locations for violets. African violets are highly subject to root and crown rot if overwatered. Use only warm water because cold water
causes spots on leaves. Buy only high quality plants;
African violet pests and diseases spread very easily among other violets. Be especially watchful for
crinkled tight crowns—a possible sign of incurable
cyclamen mites. Mealy bugs can also infest African
violets.
As an African violet ages, it tends to develop
a “neck”: beautiful leaves and flowers perched high
above a bare, leafless stem. A neck forms when the
oldest leaves turn yellow and are removed from the
stem. To improve the appearance of a short-necked
African violet, scrape the rough stem above the soil
line with a sharp knife to expose the green tissue
beneath the bark.
Then, slip the plant out of the pot and cut away
the bottom third of the rootball. Repot the African
violet up to the first set of leaves into a container
of fresh medium. New roots will emerge and grow
from the main stem.
The second method is suitable for long-necked
plants with 3 inches or more of bare stem. Using a
sharp knife, remove the rosette with 1 or 2 inches of
stem and root it in a potting mixture of equal parts
sphagnum peat moss, perlite, and vermiculite. Add
1 part sterilized potting soil if you want the pot to be
a permanent home.
Water the African violet before placing it in
a plastic bag tied off at the top with a twist-tie to
maintain high humidity levels.
Move it to a location receiving bright filtered
light.
After roots have formed, usually in about four to
six weeks, take it out of the bag. An African violet
rooted in soilless propagation medium should be repotted into a mixture containing potting soil.
Don’t toss out the original plant. Trim the
stump to about an inch high and keep the soil
moist. After a few weeks, new leaves will emerge
from the sides of the stem.
Amaryllis (Hippeastrum cvs.) – The key to
growing amaryllis is to keep the plants actively
growing after they finish blooming. Keep the plants
in full sun with a night temperature above 60 oF. As
soon as the danger of frost has passed, set the plants
in the garden in a semi-shaded spot. In the fall,
before danger of frost, bring them in, stop watering them to allow old growth to die back, and store
them in a cool (55 oF), dark place to rest for about 2
months. After its rest, bring them into a warm light
room and water moderately to begin new growth.
Azaleas – The most readily available azaleas for
cultivating and forcing indoors are the florist azaleas
(hybrids of Rhododendron indicum). If you purchase
a florist azalea in bloom, wait until the flowers fade.
Then, if the plant is growing in a peat-based medium, repot it into a medium composed of one part
of a soil-based potting mix, two parts peat moss,
and one part perlite. Move the plant to a bright,
cool location and water whenever the medium feels
dry. To improve humidity levels during the winter
months, mist the azalea every few days in the morning or run a humidifier.
After the last freeze in your area, move the plant
outdoors to a shady spot. To keep the plant at a
manageable size, prune the shoots before July 1.
Flower buds will be produced during the shorter
days of late summer. Move the plants inside before
the first expected freeze to a sunny location at 65
to 70 oF. The flower buds will remain dormant and
closed unless they are exposed to cool temperatures.
In late fall move the azaleas to a lighted room with
a temperature between 40 to 50 oF for 6 to 8 weeks.
After this time, return the plants to a 65 and 70 oF,
well-lighted room for flowering to occur. Expect the
blooms to last at least 4 to 6 weeks.
Some of the best azaleas for indoor culture are
‘Coral Bells’ and ‘Dogwood’ among the Kurume hybrids, and ‘Alaska’, ‘Dorothy Gish’, ‘Gloria Mundi’,
‘Mission Bells’, ‘Roadrunner’, and ‘White Gish’
among the Belgian, Indian, and Rutherford hybrids.
Instead of florist azaleas, other evergreen azaleas
for indoor culture include the late flowering Glenn
Dale and Satsuki hybrids.
Christmas Pepper (Capsicum annuum) – Plants
are usually available in 4- and 6-inch pots during
the fall and winter and are bought for the highly
decorative fruit. The fruit will be at peak color for 1
to 2 months. They will be brighter and last longer
if they have high light and mild temperatures (60 to
75 oF) and the soil remains moist. Fertilize weekly
with a soluble fertilizer. Be aware that these peppers are sometimes extremely hot. Keep them away
from small children. (It is also very hard to rebloom
Christmas pepper.) Frost will kill the plants.
Chrysanthemum (Chrysanthemum x grandiflorum) – Two types of mums are sold at retail outlets: pot mums (killed by frost) and garden mums.
Garden mums are generally available in the fall as
a flowering, container-grown plant. They can be
planted outdoors and are hardy through the winter.
Garden mums are perennials and will flower each
year. Pot mums are greenhouse varieties available
year-round; they provide 3 to 4 weeks of enjoyment
and should be discarded after flowering because they
are difficult to reflower. Buy pot mums when flower
buds show full color. Diffuse, bright light levels and
60 to 70 oF temperatures will prolong peak bloom.
Don’t let the leaves wilt.
Cyclamen – Cyclamens require full sunlight and
a night temperature between 50 and 60 oF. They are
heavy users of water and must be watered whenever
the soil surface feels dry. Flower buds will fail to
develop if night temperature is too high or if light is
poor.
Easter Lily (Lilium longiflorum) – Easter lilies are produced specifically for the Easter season.
Choose strong-stemmed plants with even, regular
foliage and four to six or more flower buds. Cooler
household temperatures (60 oF) prolong flowering.
Remove yellow stamens before the pollen is shed
to make the flowers last longer and keep the pollen
from staining clothing, furniture, or carpets. Easter
lilies can be transplanted outdoors in South Carolina.
After you remove the last withered flower, plant
them outside. Choose a well-drained site and mix
in a generous amount of organic matter. Space the
potted Easter lilies 12 to 18 inches apart and mulch
them deeply since lilies like their “feet in the shade
and their heads in the sun.” As the leaves and stems
of the original shoots die, prune them off. New
growth will soon emerge.
Easter lilies, which were forced to flower under
controlled greenhouse conditions on Easter, a holiday that can fall on any Sunday from March 22 to
April 25, will flower naturally in June or July and
will reach a height of 2 feet or more.
Bear in mind that lilies are extremely susceptible to viruses, which can be spread to other lilies
growing nearby.
Foliage Plants – Foliage plants have varying
light, temperature, and watering requirements. For
example, Chinese evergreen does well in very low
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light, whereas Dieffenbachia requires medium to
high light. Most can be damaged by temperatures
below 55 oF. Ideal temperature for growth is 75 to
90 oF. Ask a county Extension agent or nurseryman,
or consult a plant book for the recommended light
level for specific plants. If you keep plants several
months, fertilize them every 2 months. To avoid
salt buildup in the soil, allow generous amounts of
water to run through the pot on a monthly basis.
From time to time, clean the leaves to remove
dust. Foliage plants can be rejuvenated by placing
them in a shaded area outdoors during warm weather. Avoid placing them near windows or outdoors
during the winter to avoid cold injury.
Forced Spring Bulbs – Forced bulbs are bulbs
such as tulips, daffodils, crocuses, and hyacinths that
are exposed to chilling temperatures in a cooler or
refrigerator for several weeks and then placed in
warm greenhouses for the flowers to develop.
To get the most color and greatest longevity
from spring bulbs, buy plants when the flower buds
first show color. In most cases, the buds will open
in 1 or 2 days. To slow down flower development
and make the blooms last longer, keep plants cool.
They will tolerate temperatures down to 40 oF. Keep
plants well watered because water stress can cut the
flowering time in half. It’s not necessary to fertilize
since the plant’s useful life is 2 to 4 weeks. You may
replant the bulbs outdoors, and they may reflower
after a year or two.
Gardenia – Gardenias grown indoors need
special care. They require an acid soil and should
receive the same nutritional care as azaleas. The
night temperature should be near 60 oF and the humidity around the plant should be kept high. High
temperature and low light intensity will result in
flower bud drop.
Geranium (Pelargonium x hortorum, P. peltatum,
and P. domesticum) – Potted geraniums are typically
available March through June. Many new types
are available, including vining and hanging basket
grown cultivars. Bright light is essential to keep geraniums in flower year-round. Keep them in pots or
transplant them into the landscape once the danger
of frost has passed. They are not winter hardy and
must be brought inside before frost if you wish to
keep them. Geraniums respond favorably to having
the soil dry out between waterings.
Florists’ Gloxinia (Sinningia speciosa) –Gloxinias are very similar to African violets in the way to
care for them; however, a gloxinia needs more light
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than an African violet, so place it in a well-ventilated location receiving bright, indirect sunlight. If
you have fluorescent lights, expose the gloxinias for
at least 12 hours a day. The temperature should be
at least 65 oF.
Water your gloxinia when the medium feels
dry to the touch. Avoid wetting the leaves when
watering. Don’t let the medium dry out completely
because it will cause the developing flower buds to
abort.
When your plant has stopped flowering and
it appears to have finished its growth cycle, discontinue watering and set it aside to allow it to go
dormant. Unlike African violets, gloxinias need
to rest before reflowering. After the leaves have
dried, remove the tuber from the pot and pluck the
leaves off. Brush off the medium and store the bare
tuber in a dry, well-ventilated location out of direct
sunlight. Check the tuber monthly for signs of new
growth. Pink sprouts emerging from the tuber signal
the time for repotting. Although florists’ gloxinia
(Sinningia speciosa) is frequently sold in bloom during the winter months, it normally flowers in the
spring and summer.
Use a light, porous commercially prepared potting mixture suitable for African violets, or prepare
your own by mixing equal parts of soil, peat moss,
and perlite. Fill the pot about halfway or threequarters, and rest the tuber in the center. Add more
medium to the pot to within one-half inch of the
rim. When you’re done, the tuber should be barely
covered and resting at the bottom of a slightly concave depression. Water sparingly at first, then more
heavily as the shoots enlarge and the leaves expand.
Holiday Cactus (Schlumbergera spp.) – The
holiday cacti have become increasingly popular with
the development of several new cultivars. At least
three related species are sold in addition to a number of cultivars. All have similar cultural requirements.
The secret of good bloom seems to be one of
temperature and photoperiod control. They will
develop buds and bloom if given bright light, short
days, and night temperatures between 55 and 65 oF.
Holiday cactuses bloom best when somewhat potbound. Repotting is necessary only about once in 3
years. Full sunlight is beneficial in midwinter, but
bright sun during summer months can make plants
look pale and yellow.
Holiday cactuses require less water from October
to March than they do when growth is active from
April to September. A rest period is very important
if plants are to bloom abundantly. Short days (13
hours or more of darkness each day) should be started about the middle of September and continued for
8 weeks. Care should be taken so that the soil never
becomes waterlogged during the dark days of winter.
Florists’ Hydrangea (Hydrangea macrophylla var.
macrophylla) – Florists’ hydrangeas are native to the
warm temperate, maritime climate of Japan on the
Pacific side of Honshu Island. These have become
popular florist plants forced into flower for holidays
ranging from Valentine’s Day to Memorial Day. The
sterile showy flowers making up the rounded inflorescences may be white or various tints and intensities of pink, and blue.
It takes about a year to produce a saleable crop.
Rooted cuttings are potted up and grown during
the summer months. At this time, growers control
the color. Excepting the white cultivars hydrangea
flower color depends on the pH and the availability
of aluminum ions. An acid (5.2 to > 5.5) pH created by the addition of aluminum sulfate results in
the formation of delphinidin-3-glucoside pigment
which is a deep blue. Pink to red cultivars need
a pH above 6 and ample amounts of phosphorus,
which competes with the aluminum ions.
In early to mid-fall plants are exposed to night
temperatures from 55 to 65 oF for 6 to 9 weeks to
induce flower bud formation. After the buds have
formed, the plants are moved to a dark, location between 33 and 40 oF for an additional 6 to 9 weeks.
Following this cool storage, the hydrangeas are
ready to be forced into bloom. The temperatures for
forcing range from 55 to 80 oF and depends on how
quickly flowering plants are needed. Most cultivars
take about 12 to 14 weeks to flowers at 60 oF. Raising
the temperature will hasten flowering; lowering the
temperature will slow it down.
For an extended floral display in your home,
keep your potted hydrangea in a cool room (less
than 70 oF) and in bright indirect light. Keep the
potting medium moist and do not allow it to dry
out.
Florists’ hydrangeas are crown-hardy to zone 6.
Flowers are borne on last year’s shoots, which can be
killed by cold winter temperatures.
Hydrangeas, generally recognized as an outdoor
flowering shrub, are also available as 6- and 8-inch
flowering pot plants. They are grown to flower for
the spring holiday season. Blooms can last from 4 to
8 weeks if plants are bought as color first develops,
watered adequately, and kept at mild temperatures
(65 to 75 oF) and medium light intensity. After the
flowers fade, remove the flower heads and transplant
the plants into the landscape.
Kalanchoe (Kalanchoe blossfeldiana) – Kalanchoes are available year-round in many colors.
Flowers will last 3 to 6 weeks in mild temperatures
(65 to 80 oF) and medium light, if the plants are
kept watered. Using manufacturers’ recommended
levels of house-plant fertilizer once a month helps.
The plants will rebloom if you put them in artificial
short days (13 hours or more of darkness each day)
for 6 to 8 weeks. They can be grown successfully if
kept in sunny windows or placed outdoors in late
spring.
Miniature roses – These scaled down versions
of hybrid tea and floribunda roses have proportionally smaller stems, leaves, and flowers. They range
in height from less than 5 inches to 3 feet, and in
flower size from one-half to two inches across with a
color range as extensive as for full-size roses. They
are completely cold hardy in South Carolina.
Miniature roses indoors need lots of bright light.
A south- or west-facing location would be ideal.
Alternatively, grow them under a bank of 40-watt
cool-white fluorescent lights with the bulbs set two
to four inches above the leaves. Fertilize weekly
with a balanced liquid fertilizer mixed at one-quarter strength. After the last spring frost, move your
miniature roses outside for a summer vacation.
Spider mites are a serious pest of miniature
roses, especially those grown indoors. To reduce
their numbers, bathe each rose once a week under
running water. If you use insecticidal soap, rinse the
leaves once the mites are killed to reduce the likelihood of soap injury to the rose’s leaves.
Poinsettia (Euphorbia pulcherrima) – The colorful bracts of poinsettias may stay bright for months
if you care for them properly. To help a poinsettia
thrive in the home during the holiday season, follow
these tips:
• Make sure it receives at least 6 hours of
bright, indirect sunlight each day. Putting it in direct sunlight may fade the color of the bracts. The
bracts are modified leaves and not flowers. The
flowers are the small yellow blossoms, called cyathia,
in the center of the colorful bracts. If direct sun
cannot be avoided, filter the sunlight with a light
shade or sheer curtain.
• To prolong the bright color of the bracts, daytime temperatures should not exceed 70 oF. Don’t
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put a poinsettia near drafts, excessive heat, or dry air
from appliances, fireplaces, or ventilating ducts.
• Poinsettias require moderately moist soil.
Water them thoroughly when the soil surface feels
dry to the touch. Never let the potting mixture
completely dry out. When watering, take the plant
out of its decorative pot or cover and water until
water seeps out of the drainage hole, completely
saturating the soil.
• Do not let the poinsettia sit in standing water. This can cause root rot and could kill the plant.
Don’t fertilize when the plant is in bloom.
• Poinsettias are sensitive to cold weather. An
enclosed patio or entryway may be a suitable place
for them, if night temperatures remain above 55
o
F. Make sure the delicate bracts are well-protected
from wind and cold rain. If the temperature drops
below 50 oF, premature leaf drop will occur as a result of chilling injury.
Plants can be reflowered, although the procedure is somewhat demanding. At the end of March
or in early April, when the bracts age and begin
to fade, prune the plant back to about 8 inches in
height or to a point where there are as many empty
leaf nodes as you want shoots in the spring. The
poinsettia will look bare after pruning, but eventually vigorous new growth will emerge from the nodes
up and down the stem. Keep the plant inside near
a sunny window and continue to water it regularly
during its growing period.
When the night temperature starts to remain
above 50 oF, you can take the plant outdoors. Once
there, the pot can be placed rim-high into welldrained soil in a morning-sun/afternoon-shade location. Rotate the pot occasionally to break off the
roots growing through its drainage hole. Fertilize
the plant every 2 to 3 weeks during the spring, summer, and fall with a well-balanced, complete fertilizer, such as 10-10-10.
Around June 1, you may want to transplant the
poinsettia into a pot about 2 to 4 inches bigger than
the original inner pot. Use a soil mix that incorporates a considerable amount of organic matter such
as peat moss, compost, or leaf mold. For a bushier
plant, pinch back the shoot tips or prune back
branches. Do not pinch back after September 1.
For an 8- to 10-week period starting October 1,
the plant must be kept in complete darkness and at
temperatures between 60 to 70 oF for 14 continuous
hours each night. Keep the plant in darkness by
moving it to a dark room such as a closet or by covering it with a large box. In addition to continuous
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darkness, the plant also must receive 6 to 8 hours of
bright sunlight daily during this period.
If the night temperature climbs too high or
drops too low, flower bud setting may be delayed or
halted. Also, any stray light, such as that of a street
light or flashlight, shining near the plant during the
critical darkness period may delay or disrupt the
blooming process.
A poinsettia will set buds and produce flowers as
nights become longer. Depending on the response
time of the particular cultivar, the plant will come
into full bloom during November or December.
Orchids – Orchids are easily cared for if kept
away from intense light and cold. They do very
well under fluorescent lights or near south windows. Most orchids bloom only once a year, but the
blooms can last as long as 2 months. Fertilize only
when new leaves appear. Water often but allow the
bark medium to dry out thoroughly between waterings. Orchids can be grown outdoors under the
shade of trees after the danger of frost has passed.
Specialized Indoor Gardening
As people become experienced with indoor
plants, many find their interest gravitating to one
or two kinds of plants, such as African violets, peperomias, or rex begonias. Others want to try forms
of gardening that require slightly different rules for
success.
Terrariums
These clear-sided containers have no drain
holes and usually have a whole or partial clear
top. Our Victorian ancestors designed the first terrariums, called Wardian cases, for their prized rare
plants. Today, many kinds of containers can be
adapted for terrariums. Everything from glass jars
with wide necks to brandy snifters or old aquariums
can be used. The more the top opening is covered,
the less the evaporation. Some misting or fogging of
the interior glass is expected, but if rivulets of water
form, the humidity is too high. Remove the lid or
open the top partially for several hours. Many terrariums need to be watered only once every 2 weeks.
Water down the side of the glass to avoid disturbing
soil.
An empty container destined to be a terrarium
needs to first have a layer of gravel added to the bottom to aid in drainage. Horticultural charcoal can
be sprinkled over the pebbles to control odors. A
well-drained soil or soilless medium should be used.
All plants chosen should have the same light and
moisture requirements (Table 18.6). Exclude plants
that cannot tolerate above-average humidity. Objects such as rocks or shells can be added to create
visual interest. Terrariums should be regarded as
temporary art forms. As plants outgrow their neighbors or the terrarium, they must be replaced. Terrariums cannot be placed in direct sun; the heat can
“cook” the plants. Bright indoor light is needed.
Dish Gardens
Dish gardens are shallow containers with low
sides and no drain holes. Often plants chosen for
dish gardens are succulents that must be watered
carefully to prevent soggy soil and root rots (Table
18.7). Succulents grow slowly and do not need to
be replaced for a long time. A sandy, gravely soil
should provide adequate drainage for succulents.
Bonsai
Bonsai (pronounced bone-sigh) is a Japanese
word meaning “tray planting.” This highly specialized horticultural practice began in ancient Japan.
Bonsai could be considered the cross­roads between
science and art in the world of horticulture. Woody
plants, usually trees, are naturally or artificially
dwarfed to give them the look of ancient trees in
windswept places. Plants are both top-pruned and
root-pruned to prevent excessive growth. Many
of the trees chosen cannot exist year-round in the
house. A number must go through a period of dormancy in a protected outdoor spot each year. Other
plants can be chosen for bonsai. Before purchasing
the first plant, it’s a good idea to read extensively on
pruning, care, and training.
in pruning and shaping, are required than with most
indoor plants.
Plant Lists
Tables 18.7 through 18.14 are lists of plants that
can be cultivated in certain environments or will
withstand specific indoor conditions of light intensity and temperature. They include plants for tropical
terrariums, desert dish gardens, indoor gardening,
large containers, ground covers for interior planting
boxes, plants for dry/warm locations, vines and trailing plants, and plants for hanging baskets. Table
18.15 lists poisonous plants. ¶
References and Further
Reading
Media and Mixes for Container-grown Plants. 1988.
A. C. Bunt, Unwin Hyman Ltd., London.
Bringing the Outdoors In. 1974. P. H. Loewer, Walker and Co., NY.
Foliage Plants for the Interior. 1995. A. J. Pertuit.
EC 688. Clemson University Cooperative Extension Service, Clemson, SC.
The Complete Houseplant Survival Manual. 2005.
Barbara Pleasant, Storey Publishing, North Adams, MA.
Topiary and Standards
There are several forms of topiary. One involves intensively pruning shrubs or trees until
the clipped form resembles an animal or geometric
form. The other begins with a shaped chicken-wire
form stuffed with moss and occasionally a soilless
medium. Small cuttings of a vine such as ivy are
pinned down to the form and trained over the surface until the form is covered. Trees trimmed to
resemble balls on sticks are called standards. With
plants such as scented geraniums or rosemary, the
lower branches are removed to leave a bare stem.
The stem needs to be supported by a thin stake, and
the top is pruned for compact growth. Vines can be
trained around wire forms so the growth resembles a
wreath. In all cases, more intensive care, especially
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Table 18.7
Plants suitable for tropical terrariums.
Scientific Name
Common Name
Aglaonema commutatum
Chinese evergreen
Begonia boweri
Minature begonias
Chamaedorea elegans
Parlor palm
Cissus antarctica cv. Minima
Dwarf kangaroo ivy
Coffea arabica
Arabian coffeetree
Cordyline terminalis minima cv. Baby Ti
Dwarf ti plant
Cryptanthus bivittatus cv. Minor
Dwarf rose-stripe earth star
Dizygotheca elegantissima
False aralia
Dracaena sanderana
Ribbon plant, Belgian evergreen
Dracaena surculosa
Gold dust dracaena
Ficus diversifolia
Mistletoe fig
Ficus pumila cv. Minima
Dwarf creeping fig
Fittonia verschaffeltiiMosaicplant
Nephrolepis exaltata cv. Bostoniensis
Boston fern
Peperomia argyreiai
Watermelon peperomia
Pilea cadierei cv. Minima
Aluminumplant
Pilea microphyllaArtilleryplant
Pilea nummularifoliaCreeping-charlie
Pteris spp.
Brakeferns or tableferns
Saintpaulia cultivars
African violets
Selaginella spp.
Clubmosses, mossferns
Selaginella kraussiana cv. Aurea
Spreading clubmoss
Selaginella pallescensSweatplant
Sinningia pusilla (and other miniature species)
Miniature gloxinias
Syngonium podophyllumArrowheadvine
Table 18.8
Plants suitable for desert dish gardens.
Scientific Name
Common Name
Aloe veraMedicineplant
Astrophytum myriostigma
Bishops-cap
Cereus peruvianus cv. Monstrosus
Rock cactus, Curiosityplant
Crassula ovata
Jadeplant
Crassula muscosa
Toy cypress, Watch-chain cypress
Crassula rupestris
Rosaryvine
Echeveria secunda var. glauca and others
Hen-and-chickens
Echinocactus grusonii and others
Goldenbarrel cactus
Euphorbia lactea cv. Cristata
Crested euphorbia, Frilled-fan
Faucaria tigrina
Tigers-jaw
Gasteria bicolor var. liliputana
Minature gasteria, Ox-tongue
Haworthia fasciata and others
Zebra haworthia
Lithops spp.
Living stones
Mammillaria bocasana and others
Powder-puff cactus
Opuntia microdasysBunnyears
Pilosocereus royenii
Cylinder cactus
Rebutia kupperiana
Scarlet crown cactus
Rebutia minuscula
Red-crown cactus
Sedum acre and others
Stone crop
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722
Table 18.9
Plants that withstand adverse home conditions.
Scientific Name
Common Name
Aglaonema modestum
Chinese evergreen
Anthurium aemulum
Climbing anthurium
Aspidistra elatiorCastironplant
Chamaedorea elegans cv. Bella
Dwarf parlor palm
Cissus rhombifolia
Venezuela treebine
Crassula argenteaJadeplant
Dieffenbachia amonenaDumbcane
Dracaena fragransCornplant
Euphorbia miliiCrown-of-thorns
Ficus elastica
Indian rubbertree
Ficus benjamina cv. Exotica
Exotic fig
Hemigraphis alternata
Red ivy
Howea belmoreana
Kentia palm
Pandanus veitchii
Screw pine
Philodendron cordatum
Heart-leaf philodendron
Sansevieria trifasciataSnakeplant
Sansevieria trifasciata cv. Laurentii
Goldenstripe snakeplant
Sansevieria zeylanica
Ceylon bowstring hemp
Epipremnum aureum
Devils ivy
Syngonium podophyllumArrowhead
Table 18.10
Plants that thrive under average home conditions.
Scientific Name
Common Name
Acanthus montanus
Mountain thistle
Aechmea calyculataVaseplant
Aechmea orlandiana
Finger-of-God
Araucaria heterophylla
Norfolk Island pine
Asparagus densiflorus Sprengeri group
Emeraldfern
Begonia aconitifolia
Begonia
Begonia ulmifolia
Elm-leaf begonia
Beloperone guttata
Shrimpplant
Caladium bicolor
Angelwings
Cissus antarcticaKangaroovine
Cissus rhombifoliaVenezuelatree
Cordyline australis
Grass palm
Cryptanthus acaulis
Green earthstar
Cyrtomium falcatum
Hollyfern
Dieffenbachia maculata
Dumbcane
Epipremnum aureum
Golden pothos
Euphorbia miliiCrown-of-thorns
Ficus benghalensis
Banyantree
Ficus eburnea
Ivory fig
Grevillea robusta
Silk oak
Pedilanthus tithymaloides subsp. smallii Jacobs-ladder
Peperomia argyreia and others
Watermelon peperomia
Pereskia aculeata
Lemonvine cactus
Philodendron cordatum
Heart-leaf philodendron
Philodendron radiatum
Dubia philodendron
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Table 18.10 (continued)
Plants that thrive under average home conditions.
Scientific Name
Common Name
Philodendron giganteum
Giant philodendron
Polyscias filicifolia
Fern-leaf aralia
Philodendron bipennifolium and others
Fiddle-leaf philodendron Pilea involucrataFriendshipplant
Piper ornatum
Ornamental pepper
Polyscias scutellaria cv. Balfourii
Balfour aralia
Sansevieria trifasciata cv. Hahnii and others
Bird’s nest sansevieria
Saxifraga sarmentosa
Strawberry begonia
Schismatoglottis pictaPainted-tongue
Spathiphyllum wallissiPeacelily
Syngonium podophyllum Variegated arrowheadvine
cv. Emerald Gem Variegated
Tradescantia fluminensis (all cultivars)
Wandering-Jew
Tradescantia spathacea
Oyster plant
Table 18.11
Plants suitable for large containers.
Scientific Name
Common Name
Scientific Name
Common Name
Alocasia cuprea
Giant caladium
Alsophila australis Australiantreefern
Codiaeum variegatum pictumCroton
Dieffenbachia amoenaDumbcane
Ficus elastica cv. Variegata
Variegated India rubber plant
Ficus lyrata
Fiddle-leaf fig
Monstera deliciosa
Split-leaf philodendron Pandanus veitchii
Screw pine
Philodendron elongatum
Philodendron Philodendron giganteum
Giant philodendron Philodendron x mandaianum
Philodendron Philodendron bipennifolium
Fiddle-leaf philodendron Philodendron bipinnatifidum
Lacy-tree philodendron Philodendron wendlandii
Philodendron Polyscias paniculata cv. Variegata
Jagged-leaf aralia
Schefflera digitata
Schefflera
Strelitzia reginaeBird-of-paradise
Table 18.12
Low, creeping ground covers for interior planting boxes.
Indoor Plants
Epipremnum aureum
Devils ivy
Episcia cupreata
Flame violet
Ficus pumila
Creeping fig
Ficus sagittata
Climbing fig
Fittonia verschaffeltii
Mosaicplant
Hedera helix
English ivy
Hemigraphis alternata
Red ivy
Pellionia pulchraRainbowvine
Pellionia repens
Trailing begonia
Philodendron cordatum
Heart-leaf philodendron
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724
Table 18.12 (continued)
Low, creeping ground covers for interior planting boxes.
Scientific Name
Common Name
Pilea nummularifoliaCreeping-charlie
Saxifraga stolonifera
Strawberry geranium
Tradescantia fluminensis (all cultivars)
Wandering-Jew
Vinca major cv. Variegata
Variegated vinca
Table 18.13
Vining and trailing plants.
Scientific Name
Common Name
Anthurium pentaphyllum var. bombacifolium
Climbing anthurium
Clerodendrum philippinumGlorybower
Cissus antarcticaKangaroovine
Ficus pumila
Creeping fig
Cissus discolor
Rexbegoniavine
Vanilla planifolia cv. Variegata
Vanilla
Cissus rhombifolia
Venezuela treebine
Table 18.14
Plants suitable for hanging baskets.
Scientific Name
Common Name
Achimenes grandiflora
Big purple achimenes
Aeschynanthus parasiticus
Lobecup basketvine
Alsobia dianthiflora
Laceflowervine
Asarina erubescens
Creeping gloxinia
Asparagus plumosus
Asparagusfern
Asparagus densiflorus Sprengeri group
Emeraldfern
Begonia x hiemalis
Winter-flowering begonia
Callisia elegansStriped-inchplant
Ceropegia linearis subsp. woodiiHearts-on-a-string
Chlorophytum comosum cv. Variegatum
Spiderplant
Cissus quadrangularis
Veldt grape
Codonanthe crassifolia
Central america bellflower
Columnea x banksii
Goldfishplant
Columnea microphylla
Small-leaved goldfishplant
Commelina communis cv. Aureostriata
Varigated widows-tear
Cyanotis kewensis
Teddybearvine
Cyanotis somaliensisPussy-ears
Cymbalaria muralis
Kenilworth ivy
Davallia fejeensis cv. Plumosa
Rabbit’s foot fern
Epipremnum aureum
Devils ivy
Episcia spp. and cultivars
Episcia
Euphorbia mammillarisCorkscrew
Fittonia verschaffeltiiMoasicplant
Hatiora salicornioides
Drunkard’s dream
Hatiora gaertneri
Easter cactus
Hedera helix cultivars
English ivy
Hemigraphis alternata
Red ivy
Hoya spp.
Wax plants
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Table 18.14 (continued)
Plants suitable for hanging baskets.
Scientific Name
Common Name
Hylocereus undatus
Night-blooming cereus
Ipomoea batatas
Sweet potato
Kalanchoe spp. Kalanchoe
Lepismium houlletianum
Snowdrop cactus
Mammillaria elongata
Lace cactus
Nephrolepis exaltata cv. Bostoniensis
Boston fern
Nephrolepis exaltata cv. Rooseveltii
Tall featherfern
Nemanthus gregariusClogplant
Pelargonium Fragrans group
Scented geraniums
Pellionia repens
Trailing watermelon begonia
Pellionia pulchraRainbowvine
Solenostemon scutellariodes cv. Trailing Queen
Trailing coleus
Peperomia acuminata
Mexico pepperface
Peperomia cubensis
Cuban pepperface
Peperomia glabella cv. Variegata
Varigated peperomia
Peristrophe hyssopifolia cv. Aureo-variegata
Marble leaf
Philodendron scandens subsp. scandens f. micans Velvetleaf vine
Philodendron scandens subsp. oxycardium
Heartleaf philodendron
Pilea nummulariifolia
Creeping Charlie
Platycerium bifurcatum
Common staghornfern
Plectranthus forsteri cv. Marginatus
Candleplant
Plectranthus oertendahlii
Prostrate coleus
Phlebodium aureum
Hare’s footfern
Portulacaria afra cv. Variegata
Elephantbush
Rhipsalis baccifera and others
Mistletoe rhipsalis
Ruellia makoyanaMonkeyplant
Schlumbergera x buckleyi
Christmas cactus
Schlumbergera truncata
Thanksgiving cactus
Sedum morganianumBurros-tail
Senecio herreianus
Green marblevine
Stapelia giganteaGiant-toadplant
Stenotaphrum secundatum cv. Variegatum
Variegated St. Augustinegrass
Streptocarpus saxorum
False african violet; Dauphin violet Tradescantia pallida cv. Purple Heart and others
Purple heart
Indoor Plants
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726
Table 18.15
Poisonous plants.
Scientific Name
Common Name Poisonous Parts
Anthurium spp.
Flamingo lily
Leaves and roots (calcium oxalate crystals)
Rhododendron spp.
Azaleas and rhododendrons
Toxic resin containing andromedotoxin; found in leaves, twigs, flowers, and pollen
Caladium sp.
Caladium
Leaves and roots (calcium oxalate crystals)
Caryota mitis
Burmese fishtail palm
Berries
Codiaeum spp.
Croton
Seed contains croton oil, a purgative; seeds rarely develop on plants sold in the United States.
Cycas revoluta
Sago palm
Plant tissue contains mutagenic and teratogenic cycasin, a known carinogen and liver toxicant
Dieffenbachia spp.
Dumbcane
Leaves and roots (calcium oxalate crystals)
Epipremnum aureum
Pothos
Leaves and roots (calcium oxalate crystals)
Euphorbia spp.
Crown-of-thorns
Sap contains complex esters, carcinogens
Ficus spp.Fig
Sap
Hedera helix
English ivy
Leaves and berries contain heteragenin
Monstera deliciosa
Split-leaf philodendron
Leaves and roots (calcium oxalate crystals)
Pedilanthus tithymaloides
Japanese poinsettia; redbird cactus
Sap
Philodendron spp.
Philodendron
Leaves and roots (calcium oxalate crystals)
Phoenix dactylifera
Date palm
Pollen
Solanum pseudocapsicum
Jerusalem-cherry
Leaves and unripe fruit contain solanine,
a poisonous alkaloid
Syngonium podophyllum
Leaves and roots (calcium oxalate crystals)
Arrowheadvine
Indoor Plants
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727
Indoor Plants Review
1. Explain how a house plant differs from other types of plants.
Culture
2. Describe the general guidelines for providing light for house plants, indicating the very best light source.
3. Comment on the use and value of artificial lights.
4. Describe the ideal indoor plant temperature.
5. Indicate what environmental factor is the most difficult to provide for house plants.
6. Cite the cause of most house plant problems.
7. Describe how house plants should be watered.
8. Indicate what times of the year house plants can be fertilized.
9. Describe the appearance of a plant that has fertilizer-buildup, and how this could be remedied.
10.Describe the conditions that necessitate repotting and explain how it’s done.
11.Suggest effective and current methods for dealing with common indoor plant pests.
Related Topics
12.Cite the names of 5 easy to care for house plants.
13.Indicate how to maintain good shape in a house plant.
14.Suggest an approach to allow house plants to safely adjust to a summer outdoors.
Indoor Plants
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