Pottawatomie County Cooperative Extension Service
Oklahoma State University
14001 Acme Road
Shawnee OK 74804
Volume 7, Issue 2
July, 2011
Pottawatomie County
Horticulture Newsletter
PEONY QUESTIONS
Peonies are a favorite herbaceous
perennial, being long-lived, easy
to grow, an heirloom plant, and
coming in many colors of red,
pink and white in early summer. Here are a few questions
I've received on peonies, and answers that should help you have
great plants.
“My peonies get tall and flop
over. What can I do to prevent
this?” Many older cultivars
(cultivated varieties) are prone to
this, while many new cultivars
have been selected to have
stronger stems and to be more
stocky. So it could be just your
particular selections. Too little
light also may cause them to grow
taller (and with less blooms). If
the plants are quite old (maybe 15
to 30 years or more), they may
need dividing.
Some try to stake floppy plants,
but this can be tricky. If you put a
cage or "peony ring" around
plants before they get too tall,
plants may then flop onto the top
wire and then break there. The
trick is to get tall enough cages or
rings to hold plants upright near
the tops.
plants in the fall after leaves begin to
die back. Make sure to have at least
three plump buds or "eyes" at the
base on each division in order for
plants to establish well the following
year.
"I need to move peonies in summer,
before fall, due to construction. Is
this possible?" Yes it often is, just
make sure if moving peonies in summer to minimize damage to tops and
stems, get as much roots as possible,
keep well-watered when replanting,
and put some light cloth or fabric
over to shade from intense sun. If
you can wait until fall though to
move plants it is much easier with
greater chance of success.
“I have ants on my flowers. Is this
bad?" No, the ants are merely after
the sweet sap secreted by the flower
bud scales, or if on leaves perhaps
the secretions of aphids. So there is
no need to control them. The myth
that ants are needed to open flower
buds is just that.
“My peonies have stopped flowering. What is wrong?" Did they get
too much mulch? Peonies should be
planted at the surface, with buds no
more than two inches deep. Otherwise they may not bloom. If mulch“When is the best time to divide ing heavily around plants, keep the
mulch away from the base.
peonies, and how often should
they be divided?” Peonies can
If the buds turn brown and shrivel,
live a lifetime given sun and well- they may have gray mold or botrytis
drained soil, and may never need disease. This often appears in cool
dividing. If they get too floppy, and damp weather, and also may
large, or have few blooms, divid- cause stems to turn black. Keep
ing may help. It is best to divide plants weeded, with good air circula-
tion, and water early so plants dry
before night. Sprays are available
for this disease. Another possible
cause for small, unopened buds is
the tiny thrips insect.
”My peonies have holes in leaves,
notched edges on others. What is
eating them? More than likely slugs
are the culprit. These prefer moist
conditions to retreat to during day,
such as mulch. Keeping plants free
of mulch, with good air circulation,
may help. There are many slug control products, just make sure if using
poison baits these don’t poison nontarget animal such as pets. Some
use saucers of beer, which attracts
slugs. Others just use boards under
plants, or rolls of newspaper. Slugs
crawl under or in these, then can be
removed.
“When should I cut back peonies?" Wait until late fall, or even
early spring, to cut brown or dead
stems back. You can cut them back
once foliage has mostly turned
brown.Inside this issue:
Cont’d
Blossom End of Tomatoes 2
Boxelder Bugs
2
Help Wanted: County Fair 3
Time
Stressed Plants Look Like 3
Fall
Fall Gardening
4
Cont’d
"Will peonies produce seeds? " Yes, but this is not an easy way to start them as they may arise from cross pollination, so they do not produce the same type of plants; their seeds need special germination requirements; and
they are slow to germinate and grow, taking several years to produce a blooming plant.
“What is the best way to control weeds in peonies?" Good ground preparation prior to planting, and keeping up
with weeds, is the best control. If grass weeds get established in peonies, there may be herbicides selective for
the grass that wont hurt the peonies. Check your local garden store, and be sure to read the labels.
Otherwise, if peonies become too weedy, you may need to dig up roots in fall. Weed the area before replanting,
or replant elsewhere into clean soil. Be aware of using non-selective herbicides around peonies, such as those
with glyphosate or even the organic acetic acid (vinegar) based ones, that these can injure or kill peonies just as
they do weeds.
Blossom-End Rot of Tomatoes
Eager tomato-growers having lovingly nurtured seed to fruit have anxiously awaited their first ripe gem. But,
alas, a black leathery spot appears at the base of the fruit.
Blossom-end rot is thankfully not an infectious disease but a frustrating disorder of the fruit. The black scar tissue
thought to be caused by a deficiency of calcium in the developing fruit is usually brought on by extreme fluctuations in soil moisture.
The spot develops on the blossom end of the fruit opposite the point of stem attachment, thus the name blossomend rot. The scar is usually firm and leathery, although secondary rot organisms may enter through the damaged
tissue, causing a soft rot to develop.
Tomatoes are the species most frequently affected by blossom-end rot, but peppers, summer squash and other
cucurbit plants can also be afflicted.
There is no spray that will control blossom-end rot except maybe from the irrigation hose. Some folks recommend spraying the plants with calcium, but by the time you see the scar on the fruit, it is too late. Most Indiana
soils have plenty of calcium, although some sandy soils may be deficient.
Although the fruits that have already developed the scar cannot be helped, the new developing fruits can be. Watering during dry spells and mulching to conserve soil moisture will help reduce the fluctuations in soil moisture
and thus encourage steady growth and calcium supply in the fruits.
A FEW BOXELDER BUGS THIS YEAR
I am already getting calls about boxelder bugs. Therefore, now is the time to brush up on boxelder bug life cycles and controls. During the summer months, boxelder bugs live, feed and reproduce on trees (including boxelders, maples, ash and other shade trees and shrubs. They feed on sap from their host plants but do not cause significant damage. Boxelder bugs become nuisance pests in the fall when they leave the plants to find hiding
places for the winter. During their random search, they will congregate in the sunshine on the south sides of
buildings, trees and rocks. From there, they stray into houses through cracks in the foundation and siding, gaps
along windows and doors and other small openings.
Boxelder bugs do not reproduce indoors. Those inside the house are harmless as they do not damage the house,
its furnishings or occupants. They are a pest only because of the annoyance of their presence.
There is no easy way too determine when and where boxelder bugs will be a problem until the problem starts. By
then it may be too late for effective treatment. Boxelder bugs can be controlled on the trees in mid summer with
yard and garden insecticides but such treatments often have limited effectiveness because of the difficulty of
spraying large trees.
Cont’d
Cont’d
The best deterrence against boxelder bugs and similar invaders (e.g., crickets, attic flies and elm leaf beetles) is
still prevention of entry through caulking and sealing of possible entry sites (cracks and gaps). A lawn and garden insecticide or soapy water spray can be used on masses of boxelder bugs seen on and along the foundation in
the fall. A soapy water spray made with 5 tablespoons of liquid detergent per gallon of water works effectively
on boxelder bugs sprayed directly, but it has no residual activity. Soapy water sprays will have to be repeated
frequently. Reducing the number outdoors should limit the number that will get into the house.
Unfortunately, there is no easy cure for eliminating boxelder bugs already inside the house. They are generally
not killed by the aerosol household insecticide products, and the residual insecticides such as "ant and roach killer" are not of much benefit. A sure control for boxelder bugs already in the house is to remove them as they appear, by vacuuming, sweeping or picking them up and discarding.
Volunteers Needed!!!! Sign Up Today…..Don’t Delay
It’s getting close again to Pottawatomie County Fair time. I want to encourage gardeners to enter. The fair dates
are September 8th through the 10th. Entry day is Wednesday, September 7th. We need your help with entries
in both vegetables and flowers. You can find a copy of the fair book on our website at:
http://oces.okstate.edu/pottawatomie
I also need help again this year with taking entries and helping while the horticulture items are being judged.
Help is needed on Wednesday, September 7th from 2:30 p.m. to 7:00 p.m. and again on Thursday, September 8th from 9:00 a.m. to 2:00 p.m.
Anyone interested in helping, please call the office at 273-7683 as soon as possible. We will also have a short
training for workers in mid-August, so you can become familiar with how to help folks enter.
Stressed Plants May Look Like Early Fall
Many of our landscape plants are under stress from one or more factors this summer, including excessive heat
and humidity, insect feeding and disease infection. Some trees are losing leaves already and may be turning
color before they drop. This early defoliation is common when plants are under stress, and this season has been
quite challenging for many trees, both old and young..
The recent intense heat and humidity make it difficult for plants to keep up with water and cooling requirements,
even when soil moisture might be plentiful. One of the ways that plants cool themselves is through the process
of transpiration, the evaporative loss of water from the foliage.
When relative humidity is high, transpiration is reduced, so plant tissues may overheat. When the transpiration
rate is low, there is also reduced movement of water from the surrounding soil into the roots. So plants can still
be in moisture stress despite having sufficient soil moisture. The rate of photosynthesis (carbohydrate production) is also reduced when heat and humidity are excessive.
Stressed plants are often more susceptible to disease and insects. The warm and humid conditions have been perfect for many fungal and bacterial disease pathogens. Such diseases may start out as spots that then get larger
and may lead to leaf drop. Insects, such as borers, may be more likely to infest weakened trees.
Plants that are under such stress may initiate what appears to be fall color change and eventual leaf drop. Generally speaking, most plants can cope with early foliage loss, but other stresses may also take their toll. Plants that
were already in trouble before the excessive heat and humidity may not fare as well or perhaps even succumb.
But most plants that are otherwise healthy will recover just fine.
There is still plenty of summer to get through yet, so we gardeners will just have to wait and see what Mother
Nature has in store for us.
The Pottawatomie
County Horticulture
Newsletter is published
quarterly by the:
Pottawatomie County
Oklahoma Cooperative
Extension Service
14001 Acme Rd.
Shawnee, OK 74804
Joe Benton
405-273-7683
Oklahoma State University, U. S. Department of Agriculture,
state and Local Government’s cooperating.
The Oklahoma Cooperative Extension Service offers its programs
to all eligible persons
regardless of race,
color, national origin,
religion, sex, age, disability, or status as a
veteran and is an
equal opportunity employer.
FALL GARDENING
With all the hot weather vegetable gardeners have suffered this year, a fall garden might be
an option. Growing vegetables in fall you can take advantage of cooler weather outdoors, and
avoid most weeds and insects that have come and gone. Generally fall brings more rain, and
with less heat, you'll have less watering. Some crops prefer and grow best in cooler weather,
such as lettuce and traditional "cool season" crops as carrots, beets, cabbage and kale.
To decide what to grow, there are a couple considerations. Look at the days to maturity listed
on seed packets to see if your crops will have enough time to mature before frost. Keep in
mind some crops can be picked young, as with frequent picking of lettuce leaves, or young
beets, carrots and turnips. Radishes are a root crop best picked when mature.
Vegetables that withstand light frosts (and their days to maturity) include broccoli (50-70
days), carrots (50-60 days), cauliflower (60-80 days), cilantro (60 to 70 days), kohlrabi (60 to
70 days), leaf lettuce (40 to 60 days), mustard greens (30 to 40 days), spinach (35 to 45 days),
Swiss chard (40 to 60 days), and turnips (50-60 days). From the day you want to plant, count
out this number of days to see if your crops will mature before the usual first hard frost for
your area. Keep in mind that cultivars differ in their days to maturity, so look for ones with
the fewest days.
Hardier vegetables, surviving temperatures into the high 20s (F) include beets (50 to 60
days), (green onions (60 to 70 days), peas (70 to 80 days, longer than in the spring), radish
(25-35 days), and turnips (50 to 60 days). Hardiest vegetables, surviving temperatures to the
low 20s, include Brussels sprouts (90 to 100 days), collard greens and kale (both 40 to 65
days). Plant garlic two to four weeks before the first frost. Garlic is planted late to avoid
stimulating top growth only to be killed by cold.
Pottawatomie County Cooperative
Extension Service
Oklahoma State University
14001 Acme Road
Shawnee OK 74804
web:
We’re on the te.
ta
ks
http://oces.o
ie/
m
o
edu/pottawat