By Dana Dobias, Master Gardener
St. Fiacre, Patron of Gardeners.
Tulsa Master Gardeners and the Tulsa County Extension staff
annually field almost 50 thousand horticultural queries from phone calls
and drop-ins. These questions and answers are logged. From the
log, many frequently asked questions have been distilled and
are presented below.
If you do not find helpful information, Contact Us. The Tulsa Master Gardeners view these questions as a unique opportunity to
serve the gardening public in Northeast Oklahoma. The questions came
from YOU. THANKS!
How do I take a Soil Sample? See
the Soil Sample section of this website to learn the steps for this process: Soil Samples.
How do I get a soil test? It is always a
good idea to do a soil test and amend the soil before you plant. See the Soil Tests section of this website to learn the steps for this process.
How Do I Become a Master Gardener? Each
year a new class of Master Gardeners begins the training process by
attending an orientation. At the orientation the Tulsa Master Gardener
program is explained, and the candidates sign up for an interview. After
the interviews are complete, candidates selected are notified, and classes
begin in September. For more information about the Tulsa Master Gardener
Program, see the ABOUT TULSA MASTER
GARDENERS section on this web site.
How do I make a compost pile? All organic
matter decomposes, which is what compost is. You can do long term composting
and let mother nature take her time, or you can speed things up by doing
quick composting with a hot pile. To cultivate a hot pile turn the
composting material frequently (weekly).
When can I start planting? Early
Spring is a good time to plant dormant woody plants. The Tulsa area is not
frost-free until April 15th, but after March 15th,
chances of a severe hard frost are diminished.
How do I know if my soil is right for planting? Soil can be too wet or too dry for planting. To test your soil,
grab a handful, squeeze it into a ball, and drop it from waist high. If the
ball shatters and completely breaks apart, your soil is just right. If the
ball stays in a clod or big chunks, the soil is too wet and working in it
now could cause problems later in the summer. If the soil does not make a
ball, you either have sandy soil (which means go ahead and do the work), or
water your soil and wait several hours. Checking your soil the evening
before you plan to work can save you some
How can I prevent drought damage? From mid July to mid September, we are facing a long, hot dry spell
but there are a few things you can do to help your plants survive. Most
plants need at least an inch of water per week and it is difficult for them
to get that water if they are spritzed once in a while. Sprinkler systems
are good at spreading water all over a lawn, but not that good for deep
watering of shrubs, annuals, and perennials. Drip irrigation is easy and
affordable. It puts the water where your plants need it most, avoids leaf
diseases, and uses much less water than other methods. The MG office has
handouts and we also offer drip irrigation clinics several times per year.
Mulch is highly recommended. It holds the water and prevents evaporation. It
reduces weeds. Weeds use up water you intended for your plants and attract
pests like spider mites, and weeds make more weeds. Plus, a mulch keeps the
soil cooler which helps some plants deal with
heat better. For more information about mulches see OSU Fact Sheet 6005.
When is the growing season here in Tulsa? For horticultural guidelines, northeast Oklahoma is usually
frost-free by April 15. After March 15, however, our chances of a severe
hard cold snap are greatly diminished. Often, after March 15 perennials may
be plantedif they have been hardened off (accustomed to outdoor weather).
Wait until April 15th for any plants that are damaged by freezing
temperatures. We often get our first killing frost by November 2 (although
from year to year this varies to before Halloween to after Thanksgiving).
November 2 is the date you should use when counting backwards
for fall planting.
How do I know if I have ants or termites? Termites have straight antennae, four equal wings in shape and length,
and seem to have only a head and a body. Ants have bent antennae, two longer
and two shorter wings, and have three distinct body sections. If you still
cannot tell, bring a speciman to the Ext. Center and we can look at your
pests. OSU Fact Sheet 7312 can be of help, and see Know Your Ants
and Termites on this web site.
I found a spider in my house -- is it a
brown recluse? These spiders are seen year round. If you catch a
spider, you can bring it to the OSU Extension Center on 15th street for
identification, or you can read OSU Fact Sheets 7301 and 7312 for
information about identifying this pest and controlling it (see below).
F-7301 - VENOMOUS SPIDERS:
BROWN RECLUSE AND BLACK WIDOW
F-7312 - HOUSEHOLD PEST CONTROL
What are the webs in my trees. We were nearly
devastated by webworms last fall, are these the same? In early
Spring, they are probably Eastern Tent caterpillars and the webs are in the
crotch of the branches. Fall webworms make tents at the ends of the
branches. Diazinon, Orthene and Sevin are some of the chemicals recommended
to control these pests. Also, Bt is an organic alternative. Please remember,
spraying the entire tree can be a challenge. Diazinon and Orthene must touch
the bug to kill. Sevin, Orthene, and Bt must be eaten to kill the
caterpillars (yes, Orthene has dual action). In addition, please see Fact Sheet 7306, ORNAMENTAL AND LAWN PEST CONTROL
Are there any really good organic Bug
Killers?Yes, there are many. The most promising seem to be the
light horticultural oils, also called all-season oils. There is also Neem
oil that is applied the same way. These are more effective than conventional
insecticides in some ways because they smother the eggs and they also
control diseases by smothering the spores. Most of them have specific
temperature limitations so read the label. Often the temperature range is
30F to 90F. Although, why a person would want to be spraying anything if the
temperatures were above
90 or below 30 is beyond my range of understanding.
Will we be bothered by Armyworms again
this year? They destroyed my lawn a couple of years
ago. The summer of 2000 the Tulsa was inundated with Fall Armyworms.
Typically, we won’t see an outbreak that bad for another few years, but
you never know with nature.
Armyworms are not actually worms, they are the larvae (caterpillar) of a
moth. They love to eat grasses. If you find a patch of lawn suddenly
wilting, move the grass aside and look at the soil. If you see several
beige-gray caterpillars eating the grass at the soil-line, you probably have
armyworms. Here are your options:
- Do nothing, but maintain normal fertilizing and watering schedules. Replace the (fescue)
lawn in the fall. Bermuda grass will need a little pre-emergent
herbicide to be sure weeds
don’t start, but bermuda grass is rarely permanently damaged.
- Spray Bt (Bacillus thuringiensis), a bacteria that is harmful to
caterpillars once they eat it, but not to people or their pets, or any
wildlife you may have on your property (other than butterflies).Bt is
commonly sold as Dipel, Thuricide, and other names. Some older caterpillars
may not die immediately after eating Bt, but they do not feed.
- Apply Dursban, diazinon, or Orthene. Some of these are no longer available
for sale, but you may apply them if you have them on hand. These are toxic
to armyworms and a wide variety of pests. They are also toxic to ladybugs
and other beneficials. Follow all label directions and keep people and pets
off the area until it is dry. Do not spray these chemicals near bird
feeders or fish ponds.
Does my yard have moles or gophers? Moles and gophers are the two most common tunneling pests we have in this
part of Oklahoma. Basically, if the tunnel is raising the earth in, probably
have a mole. If there are mounds of dirt, larger than an ant hill, probably
a gopher. If you have both, you may have both pests. Gophers eat plants;
There are many items available for fighting these pests. For the best
long-term control, OSU recommends using traps. You must identify which
animal you have because the traps are different for each type of animal.
For more information about gophers see OSU Fact Sheet 9001
Why are my houseplants sticky? Check for insect problems. Many insects that suck the juices from your
house plants leave behind a sticky substance called honeydew. Common
makers of honeydew can be aphids, whiteflies, spider mites, or mealy
bugs. They are all controlled with common houseplant sprays. But these
sprays must be repeated to be effective because they don’t kill all the
bugs, and they don’t kill the eggs. All season horticultural oil is possibly
more effective for control, but it is
best to spray plants outdoors.
I have wood bees / carpenter bees drilling into
my wood. What can I do? The female bee burrows into dead wood for
a nesting place. She prefers vertical, unpainted wood. At dusk, spray with
Sevin dust, pyrethrins, or a wasp spray in the hole. Twenty four hours
later, plug the holes with cork or expandable foam available at hardware
stores. Consider painting the wood.
What is the difference between an annual and a
perennial? An annual grows for one season. It grows, sets seed, and
dies. A perennial grows year after year. The top may be winter killed, but
the roots will send up new shoots the following year.
As with most things, there are exceptions. There is one
group of plants that are called biennials. These grow for
one season (usually a mound of foliage), then rest for the
winter. A biennial then bursts forth with a large display of
flowers in the second year, and then dies.
Another exception is a tender perennial. Many of these
are tropical and subtropical plants. They may be perennial
in warmer areas and may even be perennial during some of our
milder winters. But tender perennials are often grown here
What are the pros and cons of annuals and
perennials? Annuals are often inexpensive per plant, and very
often have been bred to bloom consistently from planting time through fall.
They give a lot of bang for the buck. But you must
rework your soil and replant every year.
Perennials are more expensive per plant, but if planted
where that plant wants to be, they will perform well with
less care. Often a perennial will not bloom at all the first
season, bloom sparsely the second season and bloom profusely
thereafter. Perennials generally bloom for 4 to 6 weeks. A
few can bloom for longer times, especially if you deadhead
(remove the old flowers). If you plant the perennials in the
fall you can often get around the first season of not
What is an Ornamental Grass? Ornamental
grasses are a group of grass plants that include tender perennials (grown as
annuals), and perennials. These grass plants have been selected because they
look great in the landscape. Most have an upright or vase shape, a few of
the smaller varieties have a mound or flowing shape. Larger varieties can be
used as screens or background. Medium varieties often make good accents or
blend well in beds and borders. Small varieties often work as an edging or
even in containers. Not only does the foliage of grasses look great,
but the blooms are around for a long time.
How do I care for ornamental grasses? Ornamental Grasses generally only require one thing for
their care. They need to have the old grass removed before
they start to grow in the spring. The tops should stay on
all winter to prevent any winterkill. Cut to about 6 inches
in mid-March. If you feel you absolutely must fertilize
these grasses, a little Milorganite or slow release
fertilizer could be applied in mid-April. However, bear in
mind that over-fertilized grasses may tend to overgrow and
flop as the season goes on.
Is it time to plant my annuals and perennials? Here is a good schedule to follow: Late winter to early spring. Decide
and plan where you want to have plants for the season. Look through catalogs
possibly do a SOIL TEST.
March 15. We are past the time when we could get a severe
dip in temperatures, so it is okay to start cleaning up the
flower beds, remove the old foliage, winter mulch, and fall
leaves. You can plant hardened perennials (those that are
accustomed to cold temperatures and not a greenhouse). You
can prepare the areas where you want to put annuals.
Ornamental grasses (including monkey grass) should be cut
back now before they start to grow.
April 15th means we are officially frost free. Most annuals
and perennials can be planted now. However, some perform
better in warm soil (periwinkles, petunias, caladiums,
elephant ears, for example). It is better to wait until late
April through mid-May to plant these.
Summer. You can continue planting especially zinnias. More
importantly, make sure the plants are getting at least an
inch of water per week, keep them regularly fertilized, and
remove the old flowers.
Fall. This is a great time to dig and divide your perennials
and plant pansies and other plants for fall color.
What are Early blooming plants for our area? Hellebores start blooming in January and continue through
May. Abeliophyllum (white forsythia) blooms in Early
February followed by lilacs, viburnums, and Fothergilla.
Pansies, especially those planted in the fall, can color any
time the temperatures are warm. Of course, the best early
spring color is from tulips and daffodils.
What annuals and perennials are good to plant in the
fall? There are lovely fall bedding plants that will give you lots
of color like pansies, snapdragons, flowering kale and cabbage, and dusty
miller. As for perennials, mums and asters give a great floral display in
fall and will return next year. If they are planted now, they will develop a
strong root system and give you an astounding display in early spring if we
do not have a harsh or dry winter. (Hint:
keep them moist, but not soggy during the winter).
How do I over-winter my container plants? It
depends on what you have planted in the container. If you planted true
annuals, they need to finish their life cycle and you replant the container
next season. If it is a tender perennial, you can move it indoors, or into
the garage (many citrus and ficus trees tolerate being in the garage in a
dormant state). Even true perennials will not tolerate a frozen root zone.
So, containers can not be allowed to freeze (which could also crack the
container). Moving the container to a cool place that does not freeze (like
a garage) will insure the survival of your plant. If that is not possible,
you can bury the container up to its rim in an unused part of the garden, or
the container may be protected with hay bales or fall leaves piled several
feet thick all around. Insulating the rootball before our temperatures dip
into the teens will hopefully prevent you from having to replace the
container plant next spring.
Is bamboo a good landscape plant? Bamboo is a
very graceful, beautiful ornamental grass. Although not usually planted as a
weed, bamboo often becomes a weed as it establishes itself. Clumping bamboo
is not as invasive as running bamboo. Planting any bamboo in a container is
a good idea. Be sure it is an extra large container, keep the upper lip of
the container above the soil line, and be sure the container does NOT have
drainage holes. If bamboo has already established itself, RoundUp or Finale
are two excellent chemicals for controlling this plant. They will need
repeated sprays to keep the bamboo
When can I plant my caladiums and elephant
ears? These are tropical plants and love warm soil. Since they grow
in shady areas, it takes even longer for the soil to warm up. Wait until May
1 or even better, May 15 to plant. The four-inch soil temperature should
be at least 65°F.
How do I keep my chrysanthemums from flopping
over? If your variety is too leggy, remember to pinch them once or
twice before mid-June. After that they have their flower
buds and pinching would remove the flowers.
How do I grow ornamental gourds? If you have grown
squash or cucumbers, gourds are close relatives of these plants. You plant them
in the spring after we are frost free and the soil has warmed. The trick is
knowing how and when to harvest the gourds. There are two types of gourds: hard-
shell and ornamental. Hard-shell gourds have various shapes like, bottle,
dipper, birdhouse, etc. These should be left on the vine until after frost. Hang
them somewhere where they can completely dry (the seeds will rattle inside).
Once they are completely dry, they can be cleaned and polished or used for
craftwork. Ornamental gourds are usually smaller than hard-shells and have
bright colors, many shapes, and may be smooth or warty. They should be gathered
as they ripen. The stem of the fruit and the nearest tendril to that stem are
often brown when the fruit is ripe. Ornamental gourds will be ruined if they
freeze. You can clean your harvest with vinegar, allow them to dry for a week
and then polish with floor wax. The OSU Ext. on 15th St. has an interesting
handout about gourd curing, you
can stop by and ask for it if you want more information.
I have grown hollyhocks for years, why are they having problems this
year? They have brown spots on the leaves! This is probably a
rust disease. Rust is a fungus that leaves brown spots on the back of the
leaves. Infected leaves should be removed. You can then spray with Funginex,
Immunex, or Daconil. The rust grows when the moisture and temperature are
just right. Planting in an area with good air movement helps reduce problems
with rust. Also, don't plant hollyhocks in the same place. Rotate them
around so areas go 2 or 3 years without hollyhock plants.
Why do my hosta plants have holes in the
leaves? Slugs and snails eat these leaves in the night. Regular
insecticides will not control slugs and snails (these are mollusks, not
insects). Metaldehyde is the active ingredient in most slug bait products.
You can apply this as pellets or newer products have this as a liquid, which
you can use to make a solid line they must cross to get to the plant. Also,
there are many organic / physical methods of control including: pecan hulls
as a mulch, crushed egg shells, sweet gum balls circling the plant, (if you
can't walk on these in your bare feet neither can slugs) and diatomaceous
earth (which is no longer effective if it gets wet). Each of these
has been effective with some, but not all, Master Gardeners.
Why didn't my hydrangea plants bloom? There
are a number of possible reasons. You cannot prune these plants from mid-
July through Spring. They have set their buds and pruning them removes their
buds. If they have too much shade, they don't have enough energy to form
flower buds. If they have too little shade the stress from the previous
growing season doesn't allow for the flower buds to form. And late spring
frosts when the buds have started to emerge are just a few of the many
reasons these shrubs don't bloom. Contact us. We can help.
Will my pansies and perennials die under the snow
piles? Probably not, if annual plants like impatiens or caladiums get
frozen, they don't come back. Pansies are annuals, but they are oddballs because
they die from the heat rather that cold. Perennial plants like Black Eyed Susans
and Hostas will spring back from their roots again next spring. Pansies and
perennials will get smushed under the snow, but will probably stay dormant at a
constant 30 degrees or so (actually a protection from single digit
temperatures). The bigger killer will be when the snow melts, these plants
don't like wet roots and good drainage is essential.
Why do I have trouble getting my peony to
bloom? Most peonies must be in the same spot for 2 or 3 years before
they will bloom. They should not be planted too deeply or too shallow or they
won't bloom. They love a rich organic soil and are heavy feeders and need a
balanced fertilizer like 10-10-10. If the buds are forming and then turning
black it is probably due to quickly altering weather conditions like we are
prone to in Oklahoma. This causes a bud blast where the flower buds form, but
never bloom. There are no sprays for this condition.
If Sweet Potato 'Margarita' is an Oklahoma Proven plant
why do I have to wait to plant it? While Oklahoma Proven plants do
well in Oklahoma, you still must learn what temperatures a plant prefers. In
this case, this is a tropical plant that needs four-inch soil
temperature of at least 65°F to grow and thrive.
How do I overwinter for my gorgeous Ornamental Sweet Potato plant? The 'Margarita' and the 'Blackie' sweet potato outdo themselves for eye-popping
displays. These are true sweet potatoes and you can try to dig them, plant them
in pots and overwinter them indoors if you have a very bright window, extra
humidity, and temperatures above 60°F. You can also take several cuttings,
root them in water, pot them and make more cuttings through winter. Any plants
that survuve until May for planting again are worth the effort. You can also
treat them like, Amaryllis, caladiums, cannas, dahlias and elephant ears, by
digging the roots, drying them for 4-7 days and a shady cool place, and them
storing them in peat moss until spring. The final option is to treat them like
annuals and buy more next spring.
Why do the leaves of some of my trees and shrubs have
brown areas? This is often leaf scorch, especially if it is at the
edges of the leaves. When temperatures are high and the plant roots do not
take up as much water as the leaves let out, the leaves show damage. Try to
increase water at the dripline if the tree. This area is where the rain
would drip off at the edge of the leaf canopy. Adding a thick layer of mulch
(2 to 4 inches) from near to the trunk to the dripline can help keep the
roots cooler and hold any moisture. This will mean less stress for the tree.
Some plants like Japanese maples need a more protected site, such as under
dappled shade or an east facing site that is shaded from all afternoon sun.
If you have a young plant consider moving it in the fall.
If the brown area is not at the edge of the leaf, please bring a sample by
the MG offices at the OSU Extension Center for a diagnosis [Contact Us].
My shrub has leaves that are curling, what's causing
it? If you have many leaves over the entire plant that are
curling, there are two common reasons: 1) Wet soil whick can slow the
transfer of nutrients and cause a curling effect. This should clear up as
soon as the soil dries. 2) A chemical called 2-4,D may have been sprayed and
drifted on to the plant. This chemical is for killing dandelions and other
broadleaf weeds (if you have sprayed a weed- killer, look on the label for
the chemical name in tiny letters). But it is notorious for traveling
several houses away to wreak havoc on other broadleaf plants. Unfortunately,
those leaves will stay curled for the remainder of this growing season. For
more: 2-4,D Herbicide Drift.
Is my tree dying? It's losing a lot of leaves! Often trees start dropping leaves as a natural reaction. This does not mean the
death of the tree (except in the case of evergreens such as pines), but the tree
is certainly not happy. Plentiful rains in the spring encourage trees to put on
a lot of lush growth. During mid-July to early September the weather in
northeast Oklahoma is hotter and drier. Trees often react to this by dropping
leaves. Not only does a tree lose less moisture with fewer leaves, but the
leaves act as a natural mulch keeping the soil cooler and retaining any rain
that does fall.
A homeowner can try to increase watering, but this can be expensive. The least
expensive ways to do this are to install a drip irrigation system for watering
or to drip the hose all night at the edge of the dripline. Also, consider
something other than lawn for the area under trees. With a lawn you are putting
thousands of plants per square foot to compete with the tree for water and
nutrients. With a ground cover, shade perennial bed, or mulch, the tree has much
When do I fertilize my trees and shrubs? Ideally, you should take a soil test if you have not done one within the
last three years. If you choose not to, a good rule of thumb is to apply 3
pounds of actual nitrogen per 1000 square feet per season.
Once you figure how much you need to apply per season, you can decide how many
times you will apply it. Some people choose to apply in February, March, April,
May, June, September, and October. Others apply a third of the fertilizer in
Feb/March, the next third should be applied in late April/May/or June, and the third
in Sept./Oct. Small amounts of fertilizer are preferable to one large dose. If
you choose just one large dose, fall is the best time (if the tree is
growing in bermuda grass, wait until after the first killing frost).
This is a very light answer to this question. If you would like more in depth
information about fertilizing trees and shrubs please consult OSU Fact Sheet 6412 .
When is the best time to prune my tree or shrub? Please see Pruning on this web site.
Why is my tree dropping small branches? If the branch is
about as big around as a finger and looks like it was cut off, it is quite
possible that an insect, not a human, is to blame. An insect called a twig
girdler will select a branch, lay eggs in the branch, and then move a
little closer to the tree and sever the branch very evenly. (Please see Twig-Girdler on
this web site.) The twig drops to the ground with the sapless branch,
providing food for the larvae (baby twig girdlers). These larvae
eventually mature and start the life cycle over. Chemicals like
Dursban, diazinon, or methoxychlor have not been shown to be very
effective. These would have to be applied when they would touch the female
before she lays the eggs. (It is quite possible you would get more
chemical on yourself than on a target bug). A better method would be to
break the life cycle by getting rid of the branches. Throw them out or
bury them. A chipper-shredder may not kill the larvae. This is only a
severe problem for young trees. Older
trees generally are not adversely affected by losing a few branches.
What are the best trees to plant in Tulsa? Late winter or early spring is a good time to plant trees and shrubs, but
depends on the plant selected. The next best time is fall. Select the site for the tree,
carefully considering soil type, sunlight, and drainage, then Contact Us. We can help choose a plant for your site.
How can I ensure the best fall color on my
trees? First, you can select the color you like by shopping at
nurseries and garden centers in the fall. This way, you can see the
color for yourself, and often find a great bargain on trees the
nursery does not want to overwinter. As for the plants on your
property, they need cool nights, sunny days, and moisture to put
on the best fall display. Mother Nature must
cooperate with the temperature and sun, and you can assure that the
trees and shrubs get 1½ to 2 inches of water per week for
best fall display (check the soil before watering).
My tree/shrub has holes in the trunk, what is it and is
there anything I can do? Holes in the trunk of woody plants have two
main causes. If there are several holes in a line, it probably was a
woodpecker known as a Yellow-Bellied Sapsucker. The two best methods of
dealing with this bird are to try to scare it off (which is time
consuming), or to coat the trunk of the tree with a sticky substance
(sometimes sold as Tanglefoot). The birds don't like the
stickiness and go elsewhere.
If there are holes randomly around the trunk, it probably was a borer.
Ash, cottonwood, dogwood, flowering cherry, lilac, locust, pine, and peach
trees are just a few of the trees in our area that are attacked by borers.
Borers are the 'caterpillar' stage of a beetle. The eggs are often laid at
the soil level, but this depends on the type of borer. When the egg
hatches, the borer chews his way up in a random pattern through the wood.
Eventually, they emerge and you find the hole. Unfortunately, the EPA has
had to remove some of the best chemicals for borer control. Bayer
Advanced Garden Tree and Shrub is one of the few chemicals on the market to
If this plant is a multi-trunked shrub, such as a lilac, you can also get
control by removing the trunk with the damage. These are often older canes,
and then you have a younger, livelier shrub! See OSU Fact Sheet 7323 for more information.
Why did not my azaleas and forsythia bloom? Pruning at the wrong time is frequently the reason for no bloom on
forsythia, and azaleas. The proper time to prune these bushes (and most
plants that bloom in the spring) is during the six weeks after they finish
blooming. These plants set next year's flower buds starting in July.
Another common reason for azaleas to not bloom is our weather. It is
especially harsh for young azaleas. A plant that struggles through the heat
and drought from mid-July to mid- September may not have the extra energy
needed to set flower buds. Fall planting, proper fertilizing, watering
and mulching, and site selection (well-drained acidic soil, and not too
much sun) are the best ways to reduce stress on your plant. A final
possible reason for lack of azalea bloom could be improper fertilizing.
They should be lightly fertilized just after they finished blooming (when
you are already out there pruning and adding a fresh layer of mulch).
Fertilizing late in the season could cause a growth spurt and the
already formed flower buds could pop off.
When does one Fertilize azaleas? Spring
flowering shrubs like azaleas and forsythia should not be pruned or
fertilized after August 1st. They have already started setting their flower
buds for next spring. Pruning will remove these buds. Fertilizing could
cause a growth spurt and 'pop' the buds.
Why are my azalea leaves yellow? There are two
types of problems that cause yellow leaves on azaleas. If the leaves are
yellow with green veins, you probably have iron chlorosis. You can add
a quick source of iron to green your bushes up. If this problem
repeats itself, you may want to check your soil pH by taking a soil test.
Azaleas prefer acid soil and correcting the pH may release the
iron already in the soil. Oklahoma soils usually have adequate
amounts of iron. If you do decide to correct the pH, please remember it
does take a while to adjust the pH if that is
If the leaves are speckled, look on the back of the leaves. You will usually
see black spots called 'tar spots' which were probably deposited by lace
bugs. They are hard to see because their wings are clear. They suck the
juice from the plant and take some chlorophyll (green color), too. These can
be controlled with all-season, light summer oil, Neem oil, or insecticidal
soap. You will have to repeat the sprays weekly to keep control. Systemic
insecticides include, Cygon, Disyston, and Orthene. These work through the
system of the plant making the whole plant poisonous to insects. They last
longer and do not need to be reapplied as often as the oils or the contact
insecticides. The contact insecticides labeled for lace bugs include
chemicals such as Orthene and Diazinon. Keep in mind, if you don't see any
bugs, and they are difficult to see, they may have been eaten by ladybugs or
praying mantids. For more please see OSU Fact Sheet 7306 , ORNAMENTAL AND LAWN PEST CONTROL.
When is the proper time to prune a crape myrtle? This is probably
our most common pruning question. Dwarf varieties rarely need pruning.
Tall varieties should be pruned between March 15 and April 15 if they are
taller than you prefer. Older crape myrtles develop a beautifully mottled
bark as they age if they are not pruned severely each year. However,
in northeast Oklahoma these shrubs can be winter killed to the ground every
5 to 7 years so developing this beautiful bark is more of a challenge.
For additional information about pruning see Pruning.
What causes the white powder on the leaves of a crape myrtle? It is
probably a fungus called powdery mildew, which is very temperature and
humidity sensitive, making some years worse than others. You can
choose to monitor the disease and clean up diseased leaves as they fall. Or
you can spray weekly with a fungicide labeled for use on ornamental
trees that says it controls powdery mildew. This disease generally
disappears when the weather changes. Powdery mildew is unsightly, but it
rarely damages an otherwise healthy tree. Also, consider pruning in mid
March to allow better air movement. This can
help control the disease.
My dogwood tree has spots all over the leaves, what can
I do? This could be dogwood leaf spot or dogwood anthracnose.
Please bring a sample by the OSU Extension Office or CONTACT US because the treatments are different.
How is Dutch Elm Disease identified? The first
evidence is a wilting in one or more of the upper branches. Leaves on these
branches turn dull green to yellow and curl, then become dry, brittle,
and turn brown. Positive identification of the disease can be made at the
OSU Plant Diagnostic lab from a section of still living wood that is
showing the symptoms. The branch should be about one half inch in diameter
and be about 5 to 10 inches long. OSU Fact Sheet 7602 has a lot of information about this disease.
How do I care for my fruit tree? The key
element for juicy fruit is WATER. If you want a strong tree, with good
fruit production, you need to provide lots of water. One inch a week when it
is not bearing fruit and two inches or more per week when it is bearing
fruit. This is especially important as the fruit gets closer to ripening.
Also, trees tend to drop fruit when they are stressed. Our heat and drought
in July and August definitely stress trees.
To prevent disease and insect damage, consult the Fruit Trees Spray Schedule, Fruit Spray Schedules. If you do choose to spray be sure to read the label for the chemical
chosen. Most chemicals have a minimum number of days one must wait between
spraying and harvesting. If you need to harvest before that number of
days, DO NOT SPRAY, or choose a different chemical. For other chemical
options please Contact Us. Fertilizing fruit tree information is in OSU Fact Sheet 6232 . For proper pruning of fruit trees see Pruning Fruit Trees and Small Fruits .
Why didn't my hydrangeas bloom? There are
several types of hydrangeas, but the most commonly planted type is the
'mophead' hydrangea. There are many reasons why this plant may not bloom.
It forms the flower buds for this year on last year's stems. Pruning
is not necessary. If you decide to prune, do so during June, just
after the big flush of bloom is over. Otherwise, in mid-March, when you are
cleaning up, you only need to remove the old, dead stems. These
plants prefer light or dappled shade, and do not like afternoon sun. Too
much light and they may be so stressed during summer that they may not
set flower buds. Too much shade and the plant may not have enough
energy to set flower buds. Also, these plants often break dormancy when we
have a few warm days in January. Then winter "returns" and freezes the new
growth, and often the flower bud is frozen as well. If none of these sounds
like your problem, CONTACT US. We can help.
How can hydrangeas be made to change color? One
of the oddities of the plant kingdom is the sensitivity of some
hydrangeas to change color according to the pH of the soil. With the
pink/blue 'mophead' varieties, acid soil pushes the flowers toward blue.
You add sulfur or aluminum sulfate to the soil to make the pH acid (do
not use aluminum sulfate near azaleas or other plants of the Erica family).
If the soil is more alkaline, the flowers tend to be pink. You add lime to
the soil to make the pH alkaline.
What can be done about mistletoe? One choice is to leave the mistletoe alone. Most infestations take several
years to become threatening to the tree, and some may never be severe
enough to warrant action. Mistletoe is the Oklahoma State Flower! You can
cut it off the tree, but the roots are still there and it will probably
regrow. You can prune the entire section of limb off the tree, but this is
unattractive and may be detrimental to the tree.
Florel Fruit Eliminator is a chemical that can be sprayed on the trees, and
has been shown to suppress mistletoe, when the following guidelines are
observed: Use when the trees are dormant, two applications 2-3 weeks apart
are ideal. Use a surfactant to help the chemical stick to the mistletoe.
Avoid spraying when the temperatures are below 32°F all day long. Apply the
maximum label rate. This process does not kill the mistletoe and it will
probably be necessary to retreat in two to three years.
What are these balls all over my oak tree? These balls are called galls and older oaks tend to have them. An insect
caused these galls. It laid its eggs in the branch with a chemical that
altered the branch to grow the gall. Spraying would not control the insect
since the spray has to contact the insect and the bug is long gone by the
time you see the gall. Systemic insecticides have not been shown to
affect the eggs and larvae of these gall-forming insects. Pruning out the
affected area may help the tree to look a little better, but often it
ruins the look of the tree. Galls do not
significantly hurt a large tree.
My red-tip Photinia bushes look horrible! There are
spots and holes all over the leaves! What's attacking my plants? When the temperature and moisture are just right a fungus attacks the new
leaves on red-tip Photinia bushes. Cleaning up the leaf debris under the
shrubs can start to control this disease. Removing and replacing the top
inch of soil is your next step. You can then prune if desired (throw these
leaves away, do not compost them). Pruning them so they are more open
and allow for better air movement will help keep the leaves drier and not
allow fungus to attack again. Then start a weekly spray schedule until
the new growth matures.
What are the basic groups of bulbs? There
are two basic groups of bulbs planted in Oklahoma. Spring flowering bulbs,
which you plant in the fall, and Summer flowering bulbs which you plant in
mid to late spring. Since the purpose of this section is to explain things
in simple terms all growth forms (bulb, tuber, corm, rhizome, etc.) will be
called bulbs. Spring flowering bulbs such as tulips, daffodils, hyacinths,
crocus, grape hyacinths, ornamental alliums, lilies and a plethora of minor
bulbs can be planted in the fall. This should be done after the soil has
cooled (early November) and can be done as late as early January (if you
clean up after the holidays and find some bulbs you set aside in early
fall). Some people like to refrigerate the bulbs before planting them. This
is not necessary unless you will be waiting past early January to plant
them. Our ground stays cool for the full 12 weeks bulbs need to fully mature
the bloom here in northeast Oklahoma.
Summer flowering bulbs such as gladiolus, dahlia, cannas,
elephant ears, tuberous begonias,
caladiums, and many other minor bulbs should be purchased in
the spring and planted after April 15th.
Some should be planted after May 1 (elephant ears), and some
people like to wait until the first of June to
plant caladiums since they respond best to warm soil.
Just like so many things in this world, there are exceptions
to every rule and bulbs are the same
way. One exception is bearded irises. These have a root
growing along the ground and have leaves all
year long. They can be planted anytime the soil can be
When do I plant my bulbs? In the spring,
most of the bulbs available are not hardy for our area. For this reason you
should wait until after April 15 to plant them. In the case of caladiums and
other very tropical bulbs, you should wait until the soil thoroughly warms,
perhaps mid-May or early June. You should still buy these early if you are
picky about what colors or types of bulbs you want. Most places run out of
these bulbs and do not
reorder until next year.
During late August or early September the Spring bulbs
become available both at the Garden
Centers and through mail-order. These are the tulips,
daffodils, hyacinths, alliums, muscari (grape
hyacinths), crocus, and many minor bulbs. The planting time
for these is from mid-October through early
January. They should be planted in cool soil for the flower
to fully mature. But if you wait until the proper
time to plant, you may not have much to select from. Also,
bigger bulbs of the same kind generally mean
bigger flowers. If you compare two different tulip bulbs,
and one is larger, the larger bulb should have the
Bearded Irises can be replanted (or purchased) in the spring
or fall. These tough plants probably
don't have a bad time to be planted.
See OSU Fact Sheet 6408 for full details about a LandscapeMaintenance Schedule.
Can I still plant my bulbs? (usually early
winter) If you purchased some bulbs and found them some time later than
the optimal time to plant you can still go ahead and plant them. The
notorious time for this is after Christmas, many people are cleaning up and
find a bag of bulbs purchased in the fall. The plants may be shorter than
expected, but they should still be pretty. If you are more than 3 months
past the optimal time (past late January for Spring blooming bulbs or past
early June for Summer flowering), then plant them in a less conspicuous
place in the backyard, just in case they don't perform.
How do I plant the bulbs? Bulbs are planted the
same way as any plant, in rich well drained soil. If your soil is a heavy
clay soil, bulbs will probably perform better in raised beds. Dig the area
an inch or two deeper than the recommended depth for the bulb. If you do not
know the recommended depth, the rule of thumb of is 1½ times the
diameter of the bulb (so a 2-inch bulb would usually like to be 3 inches
deep). Then mix in some compost, fertilizer, or bone meal. Fill in the area
to the desired depth, place the bulbs and cover, being careful to not leave
any air pockets. Then water them well. If you have had trouble with your
bulbs rotting, you could try adding a ½ inch layer of sand or small
gravel just under the bulb to help drain away the
heavy, soaking rains we get.
Which way is up on the bulb? This problem
vexes many gardeners. Tulips and daffodils point up, but others do not make
it easy to figure out which way is up. If you examine the bulb carefully and
do not see any growth points, try to plant the bulb sideways. Growers, to
get a certain look in a container, plant some bulbs upside down on purpose.
Also, caladiums bought in large quantities can be distributed in a trench
and covered. Mother Nature makes bulbs smart enough to figure out which way
The leaves on my bulbs are up, what do I do to
protect them? (Spring question) Temperatures generally do not
affect the foliage of tulips, daffodils, and crocus unless they dip into the
teens or single digits. However, the flower buds are more tender and usually
start showing damage if the temperatures go into the 20's. Many flowers are
the most delicate and can be damaged by
any hard freeze.
All of this is dependant on many variables such as how wet or dry the soil
is (it is supposed to be like a wrung out sponge). Whether the plant lacks
nutrients (this is why you should fertilize regularly), the
type of soil, and whether or not we have any snow cover.
Another variable is the type of bulb. Grape hyacinths (Muscari) start
growing foliage in the fall, daffodils and tulips don't emerge until spring.
If a hard freeze is predicted, you can cover the flowers with just about any
lightweight material. The material must be long enough to touch the ground
and not let air under. You are trying to create a warm protective layer that
is not freezing. Plastic (bags or tarps) should be supported so it does not
touch the flowers. While plastic does act as a blanket, it does actually
freeze. Also, since plastic does not breathe, you must remove it as soon as
the sun is up. Old sheets can be used, they insulate well but can get heavy
if the air is damp. Row covers insulate well, lighter ones don't insulate as
well, but heavier ones might need extra support to prevent them from bending
the flower shoots. Even empty garbage cans can be inverted and cover single
plants or clumps to protect
from frost damage.
What do I do in spring when my beautiful display of
tulips, daffodils, and crocus are done? My grandmother always used
to braid the foliage. Leave the green leaves to soak up as much sun as
possible until they turn brown. The leaves are creating the flower for next
year. Greenery can be removed when it is brown and pulls out easily, usually
early June. But, do deadhead any seedheads on flower stalks that are done
blooming as this is taking energy away from next year's bloom. Braiding the
leaves would block the leaves' ability to catch the sun. You could have less
flowering next year if you braid the foliage. Consider planting daylilies in
front of your
bulbs. The new daylily leaves will mask the old bulb leaves.
Why didn't my bulbs bloom this year? There are a couple of common reasons why fall planted bulbs
don't bloom in the spring:
1) If the buds have emerged, but have turned a light brown,
it is very possible they were nipped by frost
which killed the bud;
2) If daffodils have been there for a few years and are
making foliage and not blooms, it is probably time
to dig and divide the bulbs. Daffodils double their number
every year. So, a clump of 5 bulbs becomes
10 bulbs, then 20, then 40, and then 80 by the 5th year!; or
3) Tulips do not repeat well. The Darwin tulips, Triumph
tulips, the Emperor tulips, and some of the
species tulips are most likely to be coaxed into a few years
of production. By and large, tulips want to
live in Holland, not in Oklahoma. Many people either throw
them in the compost pile or move them to
the backyard after the first year's great display.
When can I transplant my tulips and
daffodils? If your bulbs have been in the ground for a few years
and are no longer blooming, they may be too crowded. Although you could dig
and transplant the bulbs after they flower, the leaves are still making next
year's bloom. Wait until the foliage has flopped over and started to yellow,
you will still know where the bulbs are, but you also will have allowed for
the bulb to have maximum bloom next year. You will need to dig deep to get
under the bulbs so you lift the bulbs and avoid cutting into them (using a
garden fork is better because shovels and spades tend to slice through many
bulbs at once). You can immediately replant them, or you can spread the
bulbs on a open tray (like an old flat with an open mesh bottom), and dry
them in a shady place like your garage. Be sure to separate them and toss
away the damaged bulbs (they will probably rot before you can plant
them again). Then plant the bulbs in the fall.
Can I Keep My Summer Flowering Bulbs? Summer Flowering Bulbs typically are not winter hardy in our area. These
include, cannas (Canna spp.), caladiums (Caladium Spp.), elephant ears
(Colocasia), dahlias (Dahlia), Amaryllis (Hippeastrum), calla lilies
(Zantedeschia), Gladiolus (other than hardy Gladiolus, G. nanus), banana
plants, and tuberous begonias. This answer also works for the Ornamental
Sweet Potato plants. Before you say, "but I never dig my ________ up and
they do just fine!" That may be very true. Every landscape has
microclimates, which are small pockets that stay cooler or warmer than what
is typical for Tulsa. Also, our last few winters have been very mild.
Remember, every 5 to 7 years (roughly) we have a severe winter when
temperatures dip below zero. So, now that you have decided you will have to
freeze your fingers to the bone to save some money for next year, here is
what you can do: The timing is important. If the plant flops over when the
nights are cool (like caladiums) go ahead and dig it early. The bulb may
start to rot when the ground temperatures are below 40°F. If the plant
looks vigorous and is putting on a good fall display, you can probably wait
until the frost browns the above ground foliage.
Dig the bulbs. You must do this carefully or they will be damaged and rot
before spring. A garden fork is preferred, a shovel can work. Dig all around
to loosen the soil before you try to lift. You sometimes must dig deep to
get under the bulb. Garden forks have less chance of spearing your bulb. If
it is a deep bulb, you may want to scratch the soil away to find the top of
the actual bulb before digging around. Dry in a cool place away from direct
light. Some people use old flats from spring plantings, but newspaper works
well and catches much of the excess dirt. You want to dry them for 4 to 7
days to toughen the outside of the bulb and prevent damage which
could lead to rot.
Store. There are a lot of choices here. Some people prefer peat moss. Some
like to use vermiculite or perlite. Others use newspaper. One person even
pokes caladium bulbs right into a bag of pine mulch! It is wise to coat your
bulbs with a bulb protector or garden sulfur. This prevents any rot and also
keeps it from spreading and infecting all your bulbs. Also, knock off any
loose soil and inspect to be sure the bulb is healthy. Damaged bulbs rarely
survive until spring and may infect your healthy bulbs. As an option, you
can coat the bulbs with a garden fungicide. These come as dusts or liquids
(you then must dry the bulbs before storing). As some bulbs are more prone
to rotting than others, experience may tell you if this is a step you want
Finally pack them away. Again, there are many choices. You want something
that can breathe. Paper grocery bags, cardboard boxes, even burlap can hold
the bulbs and keep them until spring.
The best place to keep most bulbs is in a garage or area
that stays cool (40° to 60°F) but doesn't
freeze. If they stay warm, they may sprout too early. You
can be sure the area is not freezing by keeping
a soda bottle filled with water nearby. If the water
freezes, you need to find another spot or move them
temporarily if it is due to a bad cold snap.
Can I plant my Caladiums now? And when do I lift
them in the fall? Caladiums love warm soil and may rot if the soil
is too cool. It is often better to plant them outdoors in mid-May or early
June. Early planting outdoors can shock the bulbs and cause them to emerge
more slowly than if you waited until the soil warmed. Another option would
be to pot up the bulbs indoors and plant them outdoors when the soil is
warm. Remember, they flop over in the fall when the night temps dip below
60°F. If you are going to try to save them for next season, lift them
when you first see them flopped over. If you wait until a freeze, the ground
may be so cold that the bulbs started to rot. Then follow the instructions
for Can I Keep My Summer Flowering Bulbs.
My Cannas looked nice this year, but do I have to dig
them up in the fall? It is not necessary to dig up all your cannas
unless they are so tightly packed that they are not getting enough nutrients to
bloom. An easier idea would be to dig up some of the cannas to insure that you
won't have to buy any for next year. Wait until after the tops are browned by
frost. Dig up the roots of the ones you want to store. Cut the tops off the
roots that are to stay in the ground and throw the tops back on the roots. Cover
with additional leaves if the stalks don't make a thick mulch. For the roots to
store see Can I Keep My Summer Flowering Bulbs? Most winters the cannas in the
ground will not be frozen. For the years that they do not regrow, you will have
extra to plant. For the years they come back,
you have cannas to give away or trade.
Do I have an allergy to hyacinths? I always seem to itch
after I handle them! No, it is not an allergy. The outer `skin' or
tunic of the hyacinth (a true hyacinth, not a grape hyacinth) has tiny hooks.
These hooks embed themselves in your skin and cause itching. Rinsing the area
with water and patting dry with a towel seems to
relieve much of the itching.
Is now a good time to replant my irises? These
tough plants probably don't have a bad time to replant, just some times are
better than others. Fall is probably the preferable time, but spring or anytime
the soil can be worked is okay. Dig the root, rebuild the soil with a little
compost and/or fertilizer and replant slightly deeper than before (the soil may
settle). If they tend to flop over it would be okay to trim the leaves slightly.
Otherwise, only cut the leaves back if they are spotting with a leaf disease.
All green leaves are building flowers for next year. Fewer leaves
mean fewer flowers.
How long do I have to chill my Tulips before
planting? Hmmm, your "Southerness" is showing. In areas warmer than
northeast Oklahoma, bulbs need to be pre-chilled before planting to mature
the bloom. But in our area, the soil usually stays cool for at least 12
weeks to fully cool the bulbs and then they will put on
their best display!
When do I fertilize my lawn? Often the first week of May is the best time to fertilize warm season
grasses. For cool season grasses wait until they are actively growing
usually some time in March. Wait until May to fertilize again. For more
information click below. OSU Fact Sheet 6220, LAWN MANAGEMENT IN OKLAHOMA
When do I get rid of weeds in my lawn? What control you use depends on what weed you are trying to
zap. March 10 through April 1st is a good time to put down pre-emergent
weed control for crabgrass and summer weeds. Winter weeds like Henbit and
chickweed started growing during September. You can control these winter
weeds by applying a pre-emergent in mid-August. In most turf grasses
you can still apply chemicals containing 2,4- D, dicamba, and/or MCPP, if
the weeds are actively growing. But read the label because these can cause
damage to ornamentals and non-target plants if applied incorrectly. If the
weeds are flowering, they are close to completing their life cycle and
they will not absorb enough chemical to kill them. It is better at that
point to mow the weeds, bag the clippings and get rid of the seed. Also,
applying these normally safe broadleaf herbicides to warm season grasses
that are 25-50% green will usually injure these grasses and delay green-up.
Please see: OSU Fact Sheet
6601: BROADLEAF WEED CONTROL FOR LAWNS IN OKLAHOMA and OSU Fact Sheet 6420: LAWN MANAGEMENT IN OKLAHOMA .
My neighbor says I can spray Round-Up on my
bermuda Grass to prevent weeds. Is he right? It depends on the
time of year and how closely you inspect the bermuda grass before spraying.
Generally speaking, Bermuda grass is still somewhat greenish even in
early December. January to early February usually has 2-3 nice days.
Inspect the grass to be sure it is completely dormant (no green even down
by the soil), and then read the label to find out the temperature range for
applying it. If the temps are okay and the grass is dormant, OSU has found
this to be effective at killing winter weeds in the lawn. Just remember,
even the Oklahoma Gardening Studio Gardens (managed by OSU and aired on
PBS) damaged their turf by not checking for dormancy one year. 2,4-D and
dicamba (commonly found in WeedBGone) is also effective when sprayed in
mid January to mid February. It won't kill the bermuda grass. It will
take about a month to show its effect on the weeds, but it won't harm
the perennial flowers and shrubs like it does in April.
When can I rid my lawn of white grubs? White grubs are inactive in spring due to low soil temperatures. A spring
application of Diazinon or dursban can be effective, but late summer/ early
fall applications have been shown to be more effective. There are new
products on the market such as Merit, which was tested at OSU and found to
be most effective when applied in early to mid July. Also, Bayer Advanced
Lawn Season Long Grub Control can be applied in spring and still be
effective in fall. These newer products are replacing the diazinon and
Dursban chemicals which are being phased out by the EPA.
My lawn in covered in purple weeds, how do I
kill them? Winter weeds like henbit and chickweed started growing
last September and will not be controlled by a pre-emergent applied in the
spring. In most turf grasses you can still apply chemicals containing 2,4-D,
dicamba, and/or MCPP if the weeds are actively growing. But read the label
because these can cause damage to ornamentals and non-target plants if
applied incorrectly. If the weeds are flowering, they are close to
completing their life cycle and they will not absorb enough chemical to kill
them. It is better at that point to mow the weeds, bag the clippings and get
rid of the seed. Also, applying these normally safe broadleaf herbicides to
grasses that are 25-50% green will usually injure these grasses and delay
green-up. Please refer to OSU Fact Sheet 6601, BROADLEAF WEED CONTROL FOR LAWNS IN OKLAHOMA .
How do I care now for my cool season
lawn? (tall fescue) These grasses are slowing down and going
dormant for the summer. They need lots of water to survive the summer,
especially if the grass is less than a year old. Water at least 2-3 inches
per week and raise the mower deck as high as it will go, often 2½ inches
I have round areas in my bermuda lawn that
never greened up this year, what is wrong? You probably have
spring dead spot. OSU studies have shown that a fungus causes this during
the late autumn just as the grass goes dormant. Spraying a fungicide in late
autumn probably will not be worth the effort because the fungus is not
active. Spraying a turf fungicide may help prevent it from occurring. OSU
has found one contributing factor with Spring dead spot. Do not apply a high
nitrogen fertilizer after mid-September. A burst of new growth is extremely
susceptible to this disease. More information can be found in OSU Fact Sheet 7665
How do I control nutsedge? Nutsedge can
pop up in lawns and in flowerbeds. It forms little ‘nuts’ along the roots so
new plants spread even if the mother plant is pulled or dies. Products like
Basagran, Image, Manage, RoundUp and MSMA have all been found by OSU to give
some control over nutsedges. (Some of these can be expensive). At best a
single application will only kill 70% of the nutsedge. Pulling is also
possible. But with any method, you must repeat it at least three times when
you see new plants. Be watchful about reinfestation.
How do I control poison ivy? As with
all pests, getting this weed when it is young can yield the best results.
Products with 2,4-D, dicamba, and RoundUp are all effective when the plant
is actively growing. If you have a small plant, you can use a newspaper bag
or some other plastic bag (without any holes). Put your hand inside the bag,
grab the weed, pull the bag around the plant and tie it in the bag. Throw
the bag away. If you do come in contact with poison ivy, wash off within 15
minutes with a soap that is good at removing oil.
Bamboo is invading, how do I control it? Bamboo often becomes a weed as it establishes itself. Clumping bamboo is not
as invasive as running bamboo. Planting any bamboo in a container is a good
idea. Be sure it is an extra large container with NO drainage holes and keep
the upper lip of the container above the ground.
If bamboo already has
established itself, RoundUp or Finale are excellent at controlling this
plant, but you do need to repeatedly spray.
If you are considering
digging a trench and filling it with cement to control bamboo’s spread, OSU
recommends the trench be at least 18
Which type of fescue is best to plant? OSU tests up to 300 types of tall fescue for 3 years at a time.
Of the top 25 rated tall fescues, the differences are insignificant to the
homeowner. A homeowner will have better success trying to give the fescue
what it wants: a nicely prepared soil, a light watering each day until it
grows (then gradual watering more deeply, but less often, letting the new
grass grow as tall a you can possibly stand it. (Tall fescue prefers to grow
about 18 inches tall but allows you to cut it shorter). Also remember, most
spring sown fescue will die during its first summer. Since July and August
are the most stressful times for fescue and other cool season grasses, seed
sown in September through
mid-November has a much better chance of surviving the first year.
When do I fertilize my bermuda or zoysia
lawn? OSU recommends you fertilize warm season grasses when they
are 50% green, late April or early May. More information can be found in OSU Fact Sheet 6420, LAWN MANAGEMENT IN OKLAHOMA
My whole lawn is turning purple. How can I get
rid of these weeds? The weed that turns lawns purple in spring is
henbit. This annual weed sprouts in fall, stays tiny all winter (while
setting out a big root system). Then shoots up in the warmer
spring weather. It will then flower, make seed, and die.
Large flowering henbit plants are slowing down and will not absorb a
lot of chemical. Mowing a lawn very short and bagging the seeds is the
best way to deal with flowering henbit. Smaller henbit plants can be
controlled by an application of weed killer containing 2,4-D.
Other alternatives are to apply a pre-emergent herbicide in late August.
The products Portrait and Barricade are very good at controlling henbit,
chickweed and other weeds. Also, you can spray 2, 4-D or Round-Up in
January. It may take up to a month for these chemicals to work when the
temperatures are so cold, but Dennis Martin,
OSU turf specialist, recommends this method as an option.
“Which type of fescue is best for me to plant?” OSU tests up
to 300 types of tall fescue for 3 years at a time. Of the top 25 rated
tall fescues, the differences are insignificant to the homeowner. A
homeowner will have better success trying to give the fescue what it
wants: a nicely prepared soil, a light watering each day until it grows
(then gradually watering more deeply, but less often), letting the new
grass grow as tall as you can possibly stand it. (Tall fescue prefers to
grow about 18 inches tall and allows you to cut it shorter). Also
remember, most spring sown fescue will die during its first summer.
Since July and August are the most stressful times for fescue and other
cool season grasses, seed sown in September through mid-November has a
much better chance of surviving the first year.
“When do I fertilize my Bermuda or
Zoysia lawn?” OSU recommends you fertilize lwarm season grasses
when they are 50% green.
This is usually late April or early May.
My lawn is being overrun with crabgrass. What
are my options? Following the IPM (Integrated Pest Management)
method of dealing with plant problems, we start at the least impact on
humans and the
environment and go to the stronger options.
Do nothing. Call this year a disaster and just mow the grass to prevent
seed. Pull the weeds. However, if the crabgrass has sent runners and has 20
daughter plants, you will have very tired
Spray with a product containing MSMA or CMA. DO read the labels
carefully before you buy. These chemicals have specific temperature
limitations and sometimes cannot be used with certain sprayers. As with
so many things, spraying when the plants are small is more effective
than when they are huge.
Begin a preventative program. Using Balan, Betasan or Barricade on or
around March 15th (and repeating if you choose Balan or Betasan), you
can get very good control of crabgrass as it begins from a seed. Be
warned however, if you are heavily infested, it will take 3 years of a
good fertilizing, watering and weed preventing to get full control.
Why are the garden centers saying to apply a
pre-emergent in late summer? Everything is going to die soon. Yes,
it is time to apply a pre-emergent. Late August to Sept 15 is the
optimum time to put down a pre-emergent These chemicals create a ½ inch
barrier on the top of the soil that wont allow seeds to germinate. Look for
a pre-emergent labeled for preventing henbit, chickweed, or annual bluegrass
(Poa annua). (Henbit turnS a lawn purple in the spring, chickweed creates
a low, thick mat. Annual bluegrass is a low grassy weed, so low that the
mower doesn’t mow the seeds off). You need to spread a pre-emergent, then
water it in with a half inch of water. Don’t pull weeds
because you will be punching holes in your barrier.
My fescue is wilting and dying. Is there
anything I can do? Fescue is a cool season grass and really
struggles its first summer. It needs LOTS of water to survive summer heat.
Water at least 3 inches per week. And mow it as high as your mower will go.
Or just don’t mow it when it is already struggling. Once my fescue is
stressed, I simply leave it alone and don’t mow it until it
perks up again in the fall. The longer grass helps keep the soil cooler.
What can I grow in the shade? OSU test
results show that bermuda grass does not grow well in less than 8 hours of
sun. Zoysia is slightly more shade tolerant, but will thin in less than 6
hours of sun. OSU tests show time and again the cool season grass known as
tall fescue handles shade the best. But even tall fescue needs at least 4
hours of sun or dappled shade all day. If you have less sun than that, you
should probably consider ground cover, shade bed, a deck, or mulch.
Which Fescue grass is recommended by
OSU? Tall fescue grasses are a group of grasses that can be grown
as a lawn.OSU tests as many as 300 varieties of tall fescue and then ranks
them after 3 years. Any ofthe top 20 varieties will perform well for a
homeowner. For more information please see Current Report 6602
The more important thing to do is to follow a good program of watering,
mowing, and fertilizing. See the turf section of this website for all the
bestthings to do this month.
There are some hints that can improve your chances of having a betterlawn.
- Sow the seed in the fall. Mid-September to mid October is perfect.
- Have a soil test done and amend the soil a few weeks before sowing the seed.
- Water the seed lightly morning and evening. As the grass grows, you can cut
back to one longer watering per day. Water everyday for 2 weeks, then check
it everyday to see if needs
water for the next 6 weeks.
- Let the grass grow as long as possible before you first mow it. This grass
does tolerate mowing, but it prefers to grow about 18 inches long. The
longer you initially let it grow, the
stronger the root system will be.
- Fertilize with a high nitrogen fertilizer in November. Tests at OSU and
several other universities have shown repeatedly that a final application of
fertilizer just before the onset of winter has an amazing effect of the
growth of the lawn for the next season. (DO NOT however, do this to bermuda
grass. Fall fertilizing is a contributing factor to Spring Dead
Spot). Fertilize again when the grass begins to grow in the spring.
When do I plant fall vegetables? The time to start planting for a fall crop varies from July 15 to October
15. Please consult OSU OSU Fact Sheet 6009, FALL GARDENING
When do I plant vegetables in the spring? There are two main groups of vegetables. Warm season and cool season. Cool
season plants prefer cool soil and can often tolerate light frosts. But with
hard freezes, you may want to protect them in some way. Warm season plants
like warm soil and are not frost tolerant at all. Please consult OSU Fact
Sheet 6004 for the best times to plant and ideas for what you'd like to grow this season.
How do I find out about problems on my fruit trees? Most
of the things you do to fruit trees are to prevent attacks since damage
to leaves or fruit usually cannot be repaired. Call the MG Office at
746-3701 or check out OSU Fact Sheet 7319: Home Fruit Tree Spray
Schedule . You look up the type of fruit tree you have and you will see a
chart listing the many problems each type of tree MAY have in Oklahoma.
It tells you the right time to spray and the chemicals to use. Please
remember, if it is too late this year, your tree will give it another
try next year!
Fertilizing information is in OSU Fact Sheet 6232 .
How Do I Grow Blackberries? Most of your questions will be
answered in OSU Fact Sheet 6215 , Blackberry and Raspberry Culture for the HOme Garden.
If you still have questions call the Master Gardeners at
746-3701, or e-mail us.
What’s wrong with my tomato plants? In July generally the culprits are bacterial spot and spider
mites. Both of these can be controlled with sprays. You can bring samples by
the OSU office for a Master Gardener to diagnose, or you can check out OSU
Fact Sheets 7625, 7626, and 7627 Diseases of Tomatoes I, II, and III:
OSU Fact Sheet 7625 , Common Diseases of Tomatoes: Part I, Diseases Caused by Fungi;
OSU Fact Sheet 7626 , Common Diseases of Tomatoes: Part II, Diseases Caused by Bacteria,viruses,
and Nematodes; and
OSU Fact Sheet 7627 , Common Diseases of Tomatoes: Part III, Diseases Not caused by
Why aren’t my vegetable plants producing? There are various
reasons. If the plants are too young, they may not be ready. If the
temperatures are cool (typically late April, and May in Oklahoma), some
plants won’t set
If the temperatures are too hot (typically July, August, early
September) the pollen may be drying before the insects come to pollinate
them. You can pollinate them yourself by using a cotton swab or small
paintbrush and mixing the pollen yourself from flower to flower. If you
have recently applied pesticides, you may have reduced your population
of insects to
How do I care for my fruit tree? The key element for juicy fruit is WATER. If you want a strong
tree, with good fruit production, you need to provide lots of water; 1 inch
a week when the tree is not bearing fruit and two inches or more per week
when it is bearing fruit. Watering is especially important when fruit gets
closer to ripening. Also, trees will tend to drop fruit if they are
stressed. Heat and drought in July and
August definitely stress trees.
There is some spraying you can do, but you are mostly controlling
problems, damage done to fruits and leaves cannot be fixed by
spraying. Check the Fruit and Nuts section for more information
about Home Fruit Tree Spray Schedules. It is divided by types of fruit
and then you look up the pest or disease and will see a chemical
listed. If you do choose to spray read the label carefully. Most
chemicals have a minimum number of days you must wait between spraying
and harvesting. If you need to harvest before that number of days,
DO NOT SPRAY, or choose a different chemical. Fertilizing
information is in OSU Fact Sheet 6232. OSU Fact Sheet 6232, Fertilizing Pecan and Fruit Trees
What care should my fruit tree get now? There is some spraying you can do, but you are mostly preventing
problems since damage done to fruits and leaves cannot be fixed by
spraying. Consult Fruit Spray Schedules for specifics about what sprays your
tree may need. Also, there are new oils available that are excellent at
controlling both insects diseases and even the eggs laid by the
insects. These oils can be paraffin based, petroleum based, or even
from the Neem tree.
Fertilizing information is available in OSU Fact Sheet 6232 , Fertilizing Pecan and Fruit Trees .
Should I spray and fertilize my fruit trees now? See OSU Fruit Spray Schedules from the University of Missouri Each
different fruit tree has different diseases and pests to spray for. You
can also fertilize fruit trees now, but it is better if you do half of
the application now and half in May. More fertilizing information is in
OSU Fact Sheet 6232, FERTILIZING PECAN AND FRUIT TREES
Why does my apple/crab apple tree have brown spots all over the
leaves? This is probably a fungus called cedar apple rust.
It alternates between our eastern red cedar trees and apple trees. In
late winter or early spring there are brown balls on the cedar trees.
Pulling these off will help reduce your problem. Once the weather
warms up and get
some it rains, these balls swell and have jelly-like spikes on them. They
are spreading spores at this time, and when the spores land on an apple
tree (or close relative of the apple tree), the leaf spot result and
eventually kill the tree.
Clean up all these leaves and throw them away.
Spraying your apple tree with a fungicide from blossom time until the
galls have dried up is a way to protect the tree. More information is
available in OSU Fact Sheet F-7611 Cedar-Apple Rus t Removing the cedar tree may not provide much
control because these spores can travel up to a mile away. Look for
Cedar Apple Rust resistant varieties when you are choosing a
new apple tree.
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