Ornamental and Shade Tree
PEST MANAGEMENT
Pesticide Education
Program
A Study Guide for
Ornamental and Shade Tree
Pest Management
Acknowledgments
The following Penn State Extension publications
were used as resources: A Field Guide to Tree Fruit
Disorders, Pests, and Beneficials by the Pesticide
Education Program and Tree Fruit Team; Creating
Healthy Landscapes series by Stevie Daniels, Gregory
Hoover, Gary Moorman, Robert Nuss, David
Suchanic, and Emelie Swackhamer; Entomology
Fact Sheets by Gregory A. Hoover; Plant Disease
Information Sheets by Gary W. Moorman; Scouting
and Controlling Woody Ornamental Diseases in
Landscapes and Nurseries by Gary W. Moorman;
Woody Ornamental Insect, Mite, and Disease
Management by Gregory A. Hoover, Gary W.
Moorman, and Kerry M. Richards; Pollinator Health
and Pesticides web page by Bill Riden; and Wildlife
Nuisance and Damage Information Sheets by Margaret
Brittingham.
Department of Agriculture; Maryland Pesticide
Applicator Training Manual – Wildlife Control
Category 7C by Richard D. Kramer, Maryland
Department of Agriculture; Protecting Bees and
Pollinators from Pesticides in Home Gardens and
Landscapes, University of Massachusetts Amherst;
Repellents and Wildlife Damage Control by Michael
T. Mengak, University of Georgia Extension; Using
Commercial Deer Repellents to Manage Deer Browsing
in the Landscape by Doug Tregoning and Jonathan
Kays, University of Maryland; and Weeds of the
Northeast by Richard A. Uva, Joseph C. Neal, and
Joseph M. DiTomaso, Cornell University Press.
Photographs provided by Timothy Abbey, Rob
Crassweller, Ed Crow, Sandy Feather, Garo Goodrow,
Larry Hull, Gary Moorman, Bill Riden, and Nancy
Werner of the Pennsylvania State University;
ArborSystems; Bugwood.org; DollarPhotoClub.
com; Tom Lupp and Christopher Firme of the Forest
Pest Management Section, Maryland Department of
Agriculture; Nu-Arbor Products; Pesticide Regulation
Section of the Maryland Department of Agriculture;
Dave Shetlar of The Ohio State University; Chris
Forth and I. Love of TruGreen; United States
Environmental Protection Agency; and Urban Forest
Management Program of Fairfax County Virginia.
These additional resources were also used: A Study
Guide for Commercial Turfgrass Applicators by Joanne
Kick-Raack, The Ohio State University; Bacterial
Leaf Scorch of Shade Trees Information Sheet by
Jo-Ann Bentz, Qi Huang, and Roman Jordan,
United States Department of Agriculture - National
Arboretum; EPA Actions to Protect Pollinators
Website, United States Environmental Protection
Agency; Forest Facts – Getting Chemicals Into Trees
Without Spraying by Michael Kuhns, Utah State
University; Information Sheets on Mole Control,
Repellents for Nuisance Wildlife, and Understanding
the Strengths and Weaknesses of Repellents Before you
Buy the Hype, and Vole Control by the Internet Center
for Wildlife Damage; Integrated Pest Management
in Schools - Integrated Pest Management in Schools
- IPM Training Manual for Grounds Maintenance by
Michael Raupp, University of Maryland, and John
Davidson, Maryland Department of Agriculture;
IPM in Maryland Schools: Plant Selection and Health
Care by Paula Shrewsberry and Michael Raupp,
University of Maryland, and Ed Crow, Maryland
This manual was produced by the Pesticide Education
Program of The Pennsylvania State University with
financial support from the Pennsylvania Department
of Agriculture. The primary purpose of this manual
is to help those preparing to take the Category 06:
Ornamental and Shade Trees pesticide applicator
certification exam in Pennsylvania. Questions about
this manual should be directed to: Kerry Richards,
Ph.D., Director, at [email protected].
For more information about the Penn State Pesticide
Education Program, visit their website at:
extension.psu.edu/pesticide-education
1
Manual Coordinator
Ed Crow, Regulatory Education Specialist
The Pennsylvania State University
Technical Advisors/Reviewers
Timothy Abbey, Extension Educator
The Pennsylvania State University
Ruth Benner, Extension Educator
The Pennsylvania State University
Tom Butzler, Extension Educator
The Pennsylvania State University
Tanner Delvalle, Extension Educator
The Pennsylvania State University
Sandy Feather, Extension Educator
The Pennsylvania State University
Tom Ford, Extension Educator
The Pennsylvania State University
Chris Forth, Technical Training Manager
TruGreen
Stanton Gill, Principal Agent and Regional Extension Specialist
Nursery and Greenhouse Management, University of Maryland
Jessica Lenker, Certification and Licensing Specialist
Pennsylvania Department of Agriculture
Gary Moorman, Professor Emeritus
Ornamental Plant Pathology
The Pennsylvania State University
Emelie Swackhamer, Extension Educator
The Pennsylvania State University
Editorial Services and Graphic Design
Garo Goodrow, Multimedia Specialist,
The Pennsylvania State University
Sharon Gripp, Information Specialist,
The Pennsylvania State University
Jan Hygnstrom, Project Manager,
University of Nebraska–Lincoln
Whittney Gould, Editor,
The Pennsylvania State University
2
Introduction
Purpose/Objectives
This study guide is designed to help potential pesticide applicators prepare
for the state certification exam in ornamental and shade trees to meet the
certification requirements listed in the state and federal guidelines.
How to Use This Study Guide
For best results, follow the steps listed below:
1. Read the objectives listed at the beginning of each chapter.
2. Read the chapter and underline key facts and concepts.
3. Take notes on key ideas and list questions you may have.
4. Write answers to the self-help questions found within each chapter.
5. Check for correct answers and explanations.
This study guide reviews the basics of pest management and control. As a
professional applicator, you may have training and experience beyond the
basic materials presented here.
After studying the pesticide applicator core manual and this manual, you
should be prepared to take the core exam and the category exam to become a
certified public or commercial pesticide applicator for ornamentals and shade
trees.
3
Contents
Ornamental and Shade Tree Pest Management:
Chapter 1: Managing Ornamentals in the Landscape.............................5
Part 1: Pesticide Applicator Certification........................................................6
Part 2: Maintaining Healthy Landscapes........................................................8
Part 3: Plant with Care.................................................................................. 12
Chapter 2: Integrated Pest Management (IPM)...................................19
Part 1: Integrated pest Management for Landscapes..................................... 20
Part 2: The Diagnostic Process: Problem-solving in the Landscape.............. 21
Chapter 3: Weed Management.............................................................37
Part 1: Controlling Weeds............................................................................. 38
Part 2: Weed Types........................................................................................ 39
Part 3: Weed Life Cycles............................................................................... 41
Part 4: How Herbicides Control Weeds......................................................... 46
Chapter 4: Insect and Mite Management.............................................59
Part 1: Invasion of the Insects....................................................................... 60
Part 2: Chewing Insects: Foliar (Leaf) Feeding............................................. 62
Part 3: Chewing Insects: Borers.................................................................... 67
Part 4: Chewing Insects: Root-feeding.......................................................... 68
Part 5: Piercing or Sucking Insects: Foliar (Leaf) Feeding............................. 72
Part 6: Piercing or Sucking Insects: Stem and Trunk Feeding....................... 75
Part 7: Gall-making Insects........................................................................... 76
Part 8: Beneficial Insects............................................................................... 77
Part 9: IPM for Ornamental Insects.............................................................. 80
Part 10: Resistance Management.................................................................. 85
Part 11: Pollinator Protection....................................................................... 86
Chapter 5: Disease Management.........................................................91
Part 1: Disease Management......................................................................... 92
Part 2: Diagnosing Plant Diseases................................................................. 98
Chapter 6: Nuisance Wildlife............................................................. 111
Part 1: Dealing with Wildlife in the Landscape........................................... 112
Chapter 7: Traditional Application Methods...................................... 119
Part 1: Application Methods in Ornamental Landscapes............................ 120
Part 2: Calculating Granular and Soil Applications.................................... 124
Part 3: Calibrating Application Equipment................................................. 128
Part 4: Calculating Foliar Applications....................................................... 131
Part 5: Tank Troubleshooting and Precautions........................................... 132
Chapter 8: Specialized Application Methods...................................... 137
Part 1: Specialized Application Methods in Ornamental Landscapes......... 138
Glossary............................................................................................ 151
4
Chapter 1
Managing Ornamentals
in the Landscape
Key Terms
and Concepts
You should be able to discuss
each term or concept after
studying this chapter.
Cultural practices
Integrated Pest
Management (IPM)
Microclimate
Pest
Pest resistance
Plant hardiness
Learning Objectives
After studying this chapter, you will be able to:
1. Describe why pest management is important in the
landscape
2. Define a pesticide applicator’s role in caring for the
landscape
3. Describe why the role and selection of disease- and
insect-resistant plant material is important
4. Identify environmental factors of the landscape that
influence a plant’s health
5. Match plant material with the best growing
conditions
6. List cultural practices to maintain ornamental plants
5
Part 1:
Pesticide Applicator
Certification
This study guide is designed for
people preparing to take the pesticide
applicator certification exam for
ornamental plants. Commercial and
public applicators who need this
category primarily make applications to trees, shrubs, ornamental
plants, and flower beds in an outdoor
landscape. Applications within this
category may be for weeds, insects,
or disease control. Examples of
landscapes under this category are
those associated with:
•
Residences
•
Apartment complexes
•
Commercial buildings
•
Office buildings
•
Schools
•
Hospitals and medical centers
•
Colleges and universities
•
Government buildings
•
Parks
Commercial and public applicators
can only make pesticide applications
for the categories in which they are
certified. If you begin to apply pesticides to other types of sites beyond
ornamental plants and plant beds, you
may need to take additional category
exams.
Landscapes are complex systems made up of trees, shrubs, and flower beds. These plants are
affected by pests (weeds, insects, and diseases) that can damage them. The goal is to maintain a
healthy, vigorous, attractive landscape with minimal pest problems.
Photo: Garo Goodrow, The Pennsylvania State University
6
For example, to make applications
to residential lawns, athletic fields,
or commercial lawns, you must be
certified in the category relating to
turf management. Also, you may
need to be certified in the category
that covers right-of-way and industrial weed control if you are making
pesticide applications for controlling
weeds to commercial parking lots,
along roadsides, curbs, sidewalks, and
other similar locations.
Your Job Situation
Applicators in the ornamental
category have varied job assignments.
Because there are such a wide variety
of applicator jobs, this study manual
will contain generalities that might
not apply to individual job situations. The study manual is designed
to help you prepare for taking the
certification exam for ornamental
plants and will focus on safety, pest
identification and management,
environmental stewardship, and
following pesticide label directions.
More information about ornamental
and landscape management is
available through your county
extension office, or by visiting the
university’s website. If you have
questions about which category
you should be certified in, or what
type of applications are covered
by a category, contact your state’s
Department of Agriculture.
commercial setting, or a park,
requires the long-term use of a
combination of reliable control
methods.
It is important to monitor the pest
populations and determine if and
when control is necessary. Successful
landscape management requires a
professional who has the knowledge
and skills to carry out a number of
key tasks:
•
Maintain the landscape
properly
•
Identify problems correctly
•
Decide when action is required
by developing an aesthetic
threshold
•
Select the appropriate control
method(s) and time to act
•
Use the control method(s)
properly
Pest Management
in the Landscape
In this study manual, the term
pest will refer to unwanted plants
(weeds), insects, and diseases found
in the landscape, including vertebrates causing damage to ornamental
plants. Take grass for instance: we
want it in the lawn, but consider it a
weed in the flower bed.
Landscapes with trees, shrubs, and
flower beds are important to environmental health and also improve the
aesthetics of the surrounding areas.
Trees in urban and suburban settings
can save energy, promote healthy
communities, increase property
values, and protect watersheds.
The Pesticide
Applicator’s Role
Your goal is to achieve and maintain
a healthy, vigorous, attractive
landscape with a minimum of pest
problems. Achieving this goal,
whether in a home landscape,
Weeds are a pest in the landscape and can make the landscape look unsightly. They compete
with ornamental plants for water, light, and nutrients. Generally the weed wins, because they are
hardier and reproduce easily.
Photo: Garo Goodrow, The Pennsylvania State University
7
Part 2:
Maintaining Healthy
Landscapes
The best way to keep plants healthy is to start
with healthy plants. Healthy plants are less
vulnerable to plant pathogens (infectious
organisms, or those that cause diseases) and
insects.
Photo: Garo Goodrow, The Pennsylvania State University
Even though you may be working
with established landscapes, it is
important to understand the fundamentals of creating a landscape.
Landscapes usually have a variety
of ornamental plantings, including
flowers, ground covers, vines, shrubs,
and trees. In general, shrubs are
woody plants with one or more stems
that can grow to a height of 15 feet
or less with foliage extending to the
ground. Trees typically grow more
than 15 feet tall.
Some of the problems that you
may encounter in an established
landscape are not always caused
by pests. They could be the result
of poor planting practices in the
original landscape, or the plant not
being well suited to the growing
conditions of the site.
Healthy Plants
Some problems in the landscape are not
caused by pests. They could be the result of
poor planting practices, plants not suited for
the site, or mechanical damage caused by
mowers (pictured above) or weed eaters.
Photo: Ed Crow, The Pennsylvania State University
Common sense tells us that the best
way to keep plants healthy is to
start with healthy plants! Healthy
plants are less vulnerable to certain
insects and plant pathogens (infectious organisms, or those that cause
disease). As with the human body,
preventing a problem may be easier
than finding a cure when it comes
to having healthy, thriving plants in
the landscape. As we go through this
chapter, we will look at a number of
important factors, such as:
•
How the site influences plant
health
•
How cultural practices
influence plant health
This information forms the foundation
on which you can build a strong,
effective plant management program
to help you make informed, sound
decisions about whether a pesticide is
necessary to solve a problem.
8
Plant Stress
As you work in landscapes, you
will discover that plants sometimes
experience stress. When a plant is
stressed, it becomes unhealthy and
more vulnerable to pests such as
weeds, or certain insects, or diseases.
Being able to identify these conditions is essential in order to prevent
or alleviate these stresses. The
following are some of the stresses
that can impact plants found in the
landscape:
•
Compacted or poorly drained
soils
•
Nutrient imbalances or
excessive levels of nutrients,
as is often the case with some
micronutrients (nutrients
required for plant growth in
only small quantities)
•
Unsuitable soil pH
•
Air pollution
•
Limited air circulation
•
Plant crowding
•
Road salt injury
•
Improper plant installation
•
Inappropriate amounts of light
•
Poor irrigation practices
•
Drought
•
Extreme cold or heat
•
Wind storms
•
Hail storms
•
Mechanical damage
How the Site Influences
Plant Health
Problems in the landscape are
not always caused by pests. An
important part of creating and
maintaining a healthy landscape is
to choose plants that are suited to
the conditions of each site. Plants
placed in a site that meets their needs
usually thrive without requiring a lot
of attention, while plants planted in
a site that does not suit them will be
stressed, vulnerable to attack from
pests, and probably require more
care.
The environment can, and will, affect
the health of the plant. Know the
conditions of the landscape. How
cold does it get during the coldest
winters? How hot does it get in the
summer? What is the average rainfall
in the area? Observe how many
hours of sunlight each particular
site receives and the direction of
the prevailing winds. Another
consideration is the soil’s texture
and drainage. Does the soil have a
sandy texture that drains quickly, or
a clay texture that holds water and
may drain very slowly? Have the
soil tested to determine its nutrient
level and pH (a measure of acidity
or alkalinity). Does the plant require
sites with soils that have a narrow
pH range? The growth habits of the
plant are also an important consideration. When mature, how much
space will the plant require? What
type of root system does it have?
Knowing the requirements and
specific needs of the plants in the
landscape is important.
important that you take these factors
into consideration when evaluating
the existing plants in a landscape,
or when selecting new plants for the
landscape.
Temperature
For example, rhododendrons are
popular landscape plants because
they are evergreen and offer a
spectacular display of flowers in the
spring. Most rhododendrons require
good soil drainage, some shade,
and acid soil conditions. However,
if planted in a poorly drained area,
they are likely to be vulnerable to
plant pathogens that cause root
rot diseases. In full sun, they often
become infested with lace bugs and
other insects. If they are planted in
an alkaline soil, they are likely to
weaken and die. If the conditions
are not right for rhododendrons,
consider using another plant. If the
rhododendron is already in a poor
site, be prepared to monitor for and
manage pests associated with it.
Matching the plant’s needs with site
conditions is important. Plants can
only grow and thrive within certain
temperature ranges. When selecting
plants, consider both the lowest and
highest temperatures for the region
where they will be planted. A plant’s
ability to survive cold temperatures
is known as cold hardiness, while its
ability to survive high temperatures is
known as heat tolerance. Hardiness
is based on the average minimum
temperatures in which a particular
species of plant will survive. The
primary guide for determining plant
hardiness zones in the United States
is the U.S. Department of Agriculture’s (USDA) Hardiness Zone
map. A plant is considered suitable
for a particular area (zone) if it can
tolerate the lowest average temperatures that usually occur in a zone.
Plants used outside their hardiness
zones will be under stress, making
them more susceptible to pests.
The following environmental factors
play a big role in the health of the
plants found in the landscape. It is
Information about plant heat
tolerance is harder to obtain. The
American Horticultural Society
9
Hardiness is a plant’s ability to survive
cold temperatures. Hardiness is based
on the average minimum temperature
at which a plant will survive. The United
States Department of Agriculture
(USDA) has developed this Plant
Hardiness Zone map which is the
primary guide for determining plant
hardiness zones.
The northern part of the continental
United States is in zone 3a (-40 to -35
degrees Fahrenheit) while the southern
part of the United States is in zone 11a
(40 to 45 degrees Fahrenheit). Pennsylvania is primarily made up of zones 5
and 6, as shown in the Northeastern
United States Plant Hardiness Zone map
on page 16.
(AHS) has developed a Plant Heat
Zone map based on the number of
days that temperatures rise above
86°F.
Based on the information from
the USDA Hardiness Zone map
and the AHS Heat Zone map, you
can accurately predict how a plant
variety will tolerate the temperatures
common to a particular area.
Microclimates
Microclimates are small areas within
landscapes where the climate is different from
the overall landscape. A type of microclimate
are areas with buildings and concrete where
heat is retained keeping conditions warmer
for plants.
Photo: Garo Goodrow, The Pennsylvania State University
In addition to the regional climate,
plants also are affected by microclimate conditions. A microclimate
is a small area in the immediate
vicinity of a plant where the climate
is different from the main climate
of the landscape. For example, the
microclimate under a tree canopy
can be several degrees cooler in the
summer than in an open area away
from the tree. Plants in a sheltered
area beneath the overhang of a
roof might get little rain compared
to other parts of the landscape.
In addition, materials like brick,
concrete, or stones may retain heat
overnight, keeping surrounding
plants warmer.
Sunlight and Shade
Plants vary in the amount of light
they require. Before choosing plants
for a landscape, observe how many
hours of sun and shade a specific
site receives during the day. Plants
requiring full sun need at least 6
hours of direct sun. Many shadeloving plants can tolerate exposure
to early morning sun, but putting
sun-loving plants in a lightly shaded
area will delay and reduce their
flowering production. Pest problems
can be caused by placing a plant
in a site that does not provide
adequate sun. For example, roses
growing in the shade are vulnerable
to the fungus that causes black spot
because the fungus needs moisture
on the leaves in order to infect the
plant.
The environmental conditions of
10
light, temperature, and water are
closely related. For instance, woody
plants that prefer partial shade may
tolerate more sun if temperatures are
moderate and adequate water and
mulch are provided.
Soil Conditions
Poorly drained soil will retain a lot
of moisture and can lead to soil
saturation. When a soil is saturated,
water fills all pore spaces between
the soil particles, leaving no space for
oxygen. The lack of oxygen can stunt
a plant’s growth and over time, could
kill it. Root rot caused by certain
fungi can be a problem in waterlogged soils, as well.
While most plants need to dry out
slightly between waterings, they
cannot tolerate drought for extended
periods of time. The amount of
time varies with each plant. Many
hollies, azaleas, dogwoods, yews, and
junipers die because the soil has poor
drainage and insufficient oxygen.
Clay soils are more prone to poor
drainage because they tend to hold
more water and drain more slowly
than sandy soils.
For poorly drained sites, either
select plants that are tolerant of wet
conditions or improve the drainage.
Drainage can be improved through
the use of raised beds, drainage tile,
and/or organic matter.
Soil pH
The pH level of the soil is another
important factor since it greatly
affects the soil’s fertility and the
plant’s growth potential. Soil pH is a
measure of the acidity or alkalinity
of a soil on a numeric scale. The pH
scale goes from 0 to 14 with a pH
level of 7.0 considered neutral. Soils
with a pH level below 7.0 are acidic
while those above 7.0 are alkaline.
The soil pH for most bedding plants
should be between 5.5 and 6.5 while
most woody plants will grow in a pH
range of 6.0 to 7.0. Plants such as
azalea, blueberry, mountain laurel,
and rhododendron grow best in soils
with a pH of 5.0 to 5.5.
Air Quality and Movement
Air pollution and limited air circulation also can have a significant
impact on plant health. A landscape
located near a busy highway may
be affected by exhaust fumes.
Some landscapes may be exposed
to frequent, strong winds. Overly
delicate plants might not survive
in such conditions. On a hot day,
wind can wick moisture away from
plants, causing dehydration and
wilting. A similar situation happens
to evergreens in the winter where
they are exposed to cold winds in
combination with warm and sunny
days. This causes winter burn that
is a result of the loss of moisture
through the needles, or leaves, and
the roots inability to take up water
from the frozen ground.
Limited air circulation in the
landscape is created by tightly
clustering plants together or by
pruning the tops of plant material to
create an artificially dense crown.
Available Space
Overcrowding can stress a plant.
A plant needs enough space for its
roots to expand, and for the plant
to grow to its maximum height
without restrictions. Be aware of any
obstacles in the landscape that might
hinder the plants as they grow, such
as sidewalks, driveways, decks, power
lines, or other structures.
How Cultural Practice
Influences Plant Health
Cultural practices use environmental
modifications to help manage pests.
Some of the cultural practices
needed to maintain a healthy
landscape are watering, fertilization,
pruning, and planting resistant
varieties. These practices help keep
plants healthy so they are more
tolerant of stress and can better
survive through drought, adverse
Cultural Practices for Plant Health
Watering
Fertilizing
Planting
Resistant
Varieties
Pruning
•
Use deep and infrequent waterings
•
Be careful not to overwater or underwater
plants
•
Water in the early morning
•
Test soil to determine nutrients needed
•
Avoid overfertilizing; the result is long, leggy
roots that are easily damaged by storms and
cold weather
•
Plant in the early spring or fall
•
Plant to the proper depth
•
Make sure the hole is the appropriate size
•
Check root ball for encircling roots or to see
if the plant is rootbound
•
Choose plants bred to tolerate or resist
insects and diseases
•
Remove infested and diseased plant parts
•
Use approved pruning methods
•
Allow better air movement and light
penetration
weather, and pest problems.
Cultural practices are just one tool
of an Integrated Pest Management
(IPM) program. IPM uses a combination of various pest management
methods to develop a program
that is both effective and ecologically responsible. An IPM program
is tailored to suit each specific
landscape and its environmental
conditions. Cultural practices are
used as part of IPM to keep plants
11
healthy so they will not be vulnerable
to insects or disease. See box (on
page 11) for common cultural
practices to promote plant health.
Resistant Varieties and Plant
Selection
Select pest resistant varieties. Plant
breeders have developed many
disease-resistant varieties. For
example, the flowering crabapple
(Malus spp.) is a popular small tree
for residential landscapes, mainly
because few other trees or shrubs
approach its beauty when in full
flower. This species is plagued with
disease problems such as scab, fire
blight, cedar-apple rust, and powdery
mildew. Fortunately, disease-resistant
varieties of flowering crabapples
are available. Information about
disease resistant plant material can
be obtained from county extension
offices or through their website.
Exotic plants often are used in the
landscape. They are plants that are
not native to the area and are introduced from another area. Before
choosing an exotic plant, make sure
your growing conditions will meet
the plant’s requirements and that it
is not an invasive species that will
crowd out native plants. Sometimes,
exotic plants are more resistant to
pests than are their native relatives.
For example, Cornus kousa, an exotic
dogwood that was introduced from
the Far East, is less susceptible to
infestation by the dogwood borer
and less susceptible to anthracnose
and powdery mildew than is the
native Cornus florida, the flowering
dogwood.
Select high quality plant material and
pest resistant varieties. Use healthy,
thriving plants because they will
become established faster and are less
likely to introduce pest problems.
Illustration: Garo Goodrow, The Pennsylvania State University
The selection of high-quality plant
material is another important consideration. Use healthy, robust, thriving
plants. They will become established
more easily and will be less likely to
introduce a pest or disease problem
into your landscape. Choose healthy
plants that have no signs of harmful
insects or their damage. In the case
of woody plants, the bark should
12
be free of defects, splits, or soft
areas. The soil surrounding the roots
should be moist but well drained,
and the roots should not be growing
in circles around the root ball or
protrude from the drainage holes.
The root ball should be big enough
to support the plant.
Part 3:
Plant with Care
One of the most important steps you
can take to ensure the health and
long life of the plants used in the
landscape is to plant them correctly.
The best time to plant is either early
spring or early fall when the days
are relatively short, air temperatures are cool, and the soil remains
moist. Poor plant growth and death
are most often caused by the failure
to follow recommended planting
procedures.
How to Plant Trees
and Shrubs
Although this section describes tree
planting, these principles can be
applied to any ornamental plant.
When planting a tree, first examine
the soil at the site. The soil quality
will determine the diameter of the
planting hole. If the soil is rich and
well drained, the hole only needs to
be wide enough to allow for shifting
the plant and getting it properly
oriented. In most cases, this is about
six inches beyond the sides of the
root ball. If the soil is hard to dig,
contains lots of rocks and stones, or
clumps together, prepare a hole two
to four times the diameter of the root
ball. When digging in sticky, clay
soils, you might compress or glaze
the sides of the hole with the shovel.
Scratch the glazed surface with the
shovel or a hand rake before planting
to loosen soil so new roots can grow
into the soil.
Place the soil from the hole, called
backfill, to the side. After setting
the plant in the hole (later in the
process), you will refill the hole with
this backfill soil. New roots should
have no trouble growing from this
backfill into the soil beyond the hole.
If the backfill is amended with an
abundance of organic matter, roots
sometimes circle around within the
amended soil, rather than penetrate
into the less hospitable “native”
soil outside. Consider adding some
organic matter to the backfill soil
only if the soil quality is very poor,
contains a lot of clay or clumps, or is
very sandy. In that case, add no more
than one part well-rotted organic
matter to three parts existing soil.
Next, make sure the planting hole is
no deeper than the depth of the root
system of the plant. Find the “root
flare,” the part of the trunk that
widens out just above the first roots.
When a tree is planted correctly,
the root flare will be at the level of
the surrounding soil. All trees and
shrubs should rest on solid soil in the
bottom of the hole. This will prevent
the plant from settling too deeply
into the hole over time. When a plant
settles into a planting hole, the roots
may be deprived of oxygen needed
for growth. When planting bare-root
plants, shape the hole to fit the form
of the root system. Never bend or
twist roots to fit the hole. It is best
to prune the root to fit the hole, or
better still, to make the hole larger.
Inspect the plants before setting it into
the hole. Check bare-root plants for
evidence of split or broken roots, and
trim any damaged roots with sharp
shears in order to make a clean cut.
The root system of container-grown
plants is usually dense and often
circles the inside of the container.
Roots that are left in this circular
pattern when planted will continue to
grow in that direction and eventually
could strangle the plant.
Disrupt this circling pattern by
making several vertical cuts in
the sides of the root ball and an
X-shaped cut across the bottom with
a sharp knife. If the root system is
still very dense, tease some of the
roots out of the ball to encourage
outward growth.
If the plant is balled and burlapped,
remove all twine from around the
base of the trunk, and then check
for the type of burlap. Two types
are commonly used: synthetic and
natural. Synthetic burlap is made of
plastic; it will not decay in the soil
and will prevent outward growth
of the roots. If you are not certain
the burlap is made of natural fibers,
carefully use a match to burn a
little piece of it. Natural burlap will
turn to ash, while plastic types will
melt and form a shiny bead. Use a
sharp knife to cut plastic burlap and
Trees planted too shallow will have reduced
growth.
Illustration: Garo Goodrow, The Pennsylvania State University
Root flare
One of the most important steps for plant
health care is proper planting. The hole should
not be any deeper than the depth of the
plants’ root system. Make sure that the root
flare is at the same level as the surrounding
soil.
Planting to deeply will stunt the growth and
eventually kill the tree. The roots are deprived
of oxygen suffocating them, along with
causing the bark at the base of the trunk to
rot.
Illustration: Garo Goodrow, The Pennsylvania State University
Illustration: Garo Goodrow, The Pennsylvania State University
13
remove as much of it as possible,
being careful not to break up the root
ball. Natural burlap can be removed,
or the top portion can be folded
down along the sides of the root ball
and left under the soil in the planting
hole, where it will decompose.
If the plant has a wire basket around
the root ball, cut the top row or
two of the basket’s squares, so the
wire does not strangle the plant as
it grows. Leave the bottom part of
the wire basket intact and in place to
protect the root ball from damage.
Roots systems in containers are usually dense
and often circle inside the container. Roots
left with these circular patterns when planted
will continue to grow in that direction and
eventually strangle the plant.
Photo: Ed Crow, The Pennsylvania State University
Set the plant in the hole so the
root flare is visible at the top of the
surrounding soil level. Make certain
the plant is upright and correctly
positioned. Stabilize the plant by
placing a small amount of backfill
around the bottom of the root ball.
After setting the plant in the hole,
add more backfill and tamp or
pack it firmly with your foot. Avoid
packing the soil too tightly because
you do not want to destroy the pore
space between soil particles.
Watering New Plants
When watering make sure to soak the soil.
Avoid shallow, frequent watering because it
promotes shallow root growth that will be
vulnerable to drying out. Watering bags, as
shown above, are available that provide a slow
release watering system.
Photo: Garo Goodrow, The Pennsylvania State University
Water the plant weekly during the
first year, except during weeks when
it rains enough to wet the top six
inches of soil. When you water, be
sure to soak the soil by allowing a
hose to trickle slowly at the base
of the plant and at the edges of
the backfill soil. Move the hose
around a tree or shrub bed to assure
uniform water application. Avoid
shallow, frequent watering because
it will encourage the growth of
shallow surface roots, which will be
vulnerable to drying out. Be careful
not to overwater. In general, apply
1 gallon of water per square foot of
root zone once per week. Frequent
saturation of the surrounding soil in
poor drainage areas could smother
the root system. Water only when
the soil under the surface is dry to
the touch. Continue to monitor new
trees for drought stress into their
third season. They may suffer from
14
insufficient water even when other
established plants in the landscape
are thriving. Commercial watering
bags are available that can be placed
around trees and shrubs. These bags
hold a reservoir of water and have
small holes in the bottom of the bag
to provide a slow release watering
system.
Pruning
Correct pruning may help stop
the spread of pests. Pruning out
and destroying the twigs damaged
by pests can help control the next
generation of certain pests. For
example, the twigs of trees with
viable egg masses of the Eastern
tent caterpillar can be pruned
from December through March
before the eggs hatch. Pruning out
infected plant parts can help control
diseases, as well. For example,
fire blight is a disease that affects
apples, crabapples, and pears. The
pathogens initially infect small twigs
but then grow into the main stem.
Prune during dry weather, preferably
in the winter, making the cut 6 to
12 inches below the infected area.
Disinfect cutting blades between
each cut to prevent further spread
of the pathogen that causes this
disease. Alcohol wipes or household
disinfectants can be used. Some
plant diseases can be controlled by
pinching off diseased parts such as
flowers or leaves.
When pruning to control the size
or shape of trees and shrubs, where
you make the pruning cut has a
direct effect on plant health. Prune
a branch to just outside the branch
collar, which is the swelling at the
base of a branch where the bark
from the branch and trunk meet. The
collar contains protective chemicals
that guard the tree trunk from microorganisms that cause decay. When
making pruning cuts do not injure
the branch collar because that is
where the wood can heal itself.
If you must prune tree branches
more than 2 inches in diameter,
make a series of three cuts to reduce
the weight of the limb and avoid
tearing the bark. Make the first cut
on the underside of the limb approximately ¼ to 1/3 of the way through
the branch. The second cut is made
a short distance above the first cut
removing the limb, and the third cut
is made below the first cut outside
the branch bark ridge, removing the
stub. Remember to make the third
cut just outside the branch collar.
The same process is used for pruning
dead branches. If you leave a long
stub, fungi will begin to rot the stub
and eventually could enter the trunk.
Wounds treated with a wound
dressing do not heal any faster than
those left untreated. In fact, wound
dressings are not recommended
as they may favor the development of certain decay-causing
microorganisms.
Importance of Plant
Selection
Identify key plants in the landscape
that are susceptible to pest problems.
Also, identify key pests that can
cause serious damage, or plant loss.
For instance, in a landscape that has
white birches, it is important to know
that most of them are very susceptible to bronze birch borer. Often
crabapples are susceptible to a disease
called apple scab. Know how to
properly identify plants and learn the
key pests that are likely to damage
those plants, so you can anticipate
when control actions will be needed.
Being familiar with the common
plants and pests in your area is
important for a landscape manager.
You should be able to identify the
plant and the pest at the same time—
each influences the other.
Proper Pruning
Dead Branch
Pruning
Live Branch
Pruning
Branch bark ridge
Branch bark ridge
Cut B
Cut B
Cut A
Cut A
Cut C
Cut C
Branch Collar
Branch Collar
When pruning tree branches more than 2 inches in diameter make a series of three cuts
to reduce the weight of the branch to prevent tearing the bark.
Step 1 (Cut A): Make a cut on the underside of the limb about ¼ to 1/3 of the way through the limb.
Step 2 (Cut B): This cut is made a short distance above the first cut removing the limb.
Step 3 (Cut C): The final cut is made below the first cut (A) outside the branch collar
to remove the stub.
Illustration: Garo Goodrow, The Pennsylvania State University
We will further explore these
concepts more in the next chapter,
which focuses on diagnosing
landscape problems.
15
This is a more detailed Plant Hardiness Zone map for the Northeastern United States. Pennsylvania ranges in plant hardiness from
zone 5a (-20 to -15 degrees Fahrenheit) in McKean county to zone 7b (5 to 10 degrees Fahrenheit) in the Philadelphia area.
16
Putting It Together
Exercise 1.1
Case Studies
1. You have a new client who is
giving you a tour of her yard.
She is very upset about some
shrubs that always seem to
have diseases. The shrubs look
overgrown and have not been
pruned in a long time.
Why would it be beneficial to
prune the shrubs?
____________________________ ____________________________ ____________________________ ____________________________
2. Your client decides to renovate a
portion of his landscape. He asks
for your input on what plants to
install. You recommend some
resistant varieties of plants.
Why would this recommendation
be beneficial for the landscape?
____________________________ ____________________________ ____________________________ ____________________________
3. You have a client who is giving
you a tour of her yard following
a winter with normal average
temperatures for the area. She is
very upset that the gardenias she
planted last year are now dead.
She lives in USDA Zone 6 and
the planting recommendations
for gardenias are for up to Zone 8.
Why didn’t the gardenias survive
the winter?
____________________________ ____________________________ ____________________________ ____________________________
____________________________
See answers on page 18.
17
Exercise 1.1 Answers
1. Pruning the bushes opens up the
canopy and allows air to circulate
around the leaves. This will help
dry the leaves more quickly after
rain and dews, which will help
reduce favorable conditions for
diseases to develop.
2. Resistant varieties are designed
to help reduce insect and
disease pressure on a plant.
Having resistant varieties in the
landscape will help reduce the
number of stressed plants and
encourage healthier ornamentals.
3. The USDA has established
Hardiness Zones based on the
average winter temperature
for a given area and a plant’s
ability to survive the winter at
these temperatures. Zone 8 has
a much warmer average winter
temperature than Zone 6 so the
gardenias were killed as a result
of being planted in an area that
is too cold for them to survive
the winter. In the future, this
client needs to select plants that
are rated for Zone 6 or lower.
18
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