Tuesday, August 15, 2017 0 comments By: Jack Downer

Armyworms in Turfgrass

Lawn Armyworm Diagnosis and Control

Allan Robinson: Ask a Master Gardener
Tuesday, August 15, 2017
Q: Something is eating my grass, and my neighbor says he thinks these are armyworms. How do I tell if they are armyworms and what should I do? A.M., Tulsa
A: Armyworms are not actually worms. They are the larvae, or caterpillar, of a moth, and they love to eat grassy plants. They prefer grain crops (peanuts, cotton, soybean, wheat), but they can spill over into nearby lawns and move from lawn to lawn from there. Large numbers can consume all above-ground plant parts, and they are capable of killing or severely retarding the growth of grasses. The overall numbers are more pronounced in dry years.
Fall armyworms don’t necessarily wait until the fall to do their damage. Larvae are present by late July, so they are here now. They produce several generations per summer, but the September generation is the one that damages lawns.
Caterpillars or mature larvae are green, brown or almost black and about 1½ to 2 inches long, with black and reddish brown stripes on each side of the body and four small, black spots on the dorsal side of each abdominal segment, with a marked pale, inverted “Y” on the front of the black head capsule.
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. But, to effectively search for them, mix one tablespoon of liquid dish washing soap to a gallon of water and pour it onto a square-foot area of grass. This should bring worms to the surface within a few minutes, and you can see them by separating the blades of grass. You should do this on two or more areas of the lawn and compare results.
If you find two to three worms per area, you should treat the lawn
Garden tips
  • It is not advisable to use post-emergent broadleaf weed killer during the peak heat of summer. Wait a bit. Weeds will start to grow when it cools.
  • The birds need a handy source of water, as well as food. Put out a big saucer of water and watch them not only drink but also take baths to cool off and remove parasites. Another saucer of water filled with stones and sand will be a watering hole for butterflies and other beneficial insects.
  • If you are seeing scattered tips of limbs on trees turning brown with some falling to the ground appearing to be broken off, this is likely cicada damage. The adults dig into the bark of a stem about 6 inches from the tip and lay eggs. The limb tip usually dies and may fall to the ground. It commonly involves oaks, but other trees can be affected as well. The amount of damage is nominal and will be of little consequence.

Tuesday, August 8, 2017 0 comments By: Jack Downer

Cicadas--Loud but Harmless to Plants

Cicadas--Loud but Harmless

Brian Jervis: Ask a Master Gardener

Tuesday, August 8, 2017
Q: It seems like there are so many cicadas this year. Are they going to hurt my plants in any way? GM

A: We have been getting calls in our diagnostic center from people trying to identify these beetle-like insect shells they are finding in their yards and wanting to know what that loud sound is coming from their trees. The shells and the sound are from cicadas, and if you aren’t from Oklahoma, the sheer volume a tree full of cicadas are capable of generating can be unnerving. But for locals, it reminds us summer is here.
There are several types of cicadas. The species we are most familiar with is called the Dog-Day Cicada. These cicadas typically have a life cycle of between 2 and 5 years. The sound you hear coming from the trees is actually the male cicada singing to attract females. The males produce this sound by rapidly beating their wings against their abdomen. On each side of the abdomen, there is a specialized organ called tympana, which increases the sound of this beating considerably. These mating calls have been recorded as loud as 108 decibels, which is about the same sound level as an automobile horn from about 3 feet away.
Once the male’s singing has attracted a willing partner, the female cicada lays her eggs into twigs and small branches using a somewhat saw-like egg-laying structure called an ovipositor. Six to seven weeks later, the small nymphs hatch, drop to the ground and burrow into the soil, sometimes several feet deep, where they live out the majority of their lives growing through several growth stages called instars.
When they are ready, the fully developed cicada nymphs burrow out of the ground at night, leaving an exit hole about the size of a nickel. Once out, they climb up onto a tree, fence or low plant where the adult cicada emerges from its final nymph stage, leaving behind that light brown shell or exoskeleton with which we are familiar. These adults can live 5 to 6 weeks during which the process of finding a mate begins again.
Oklahoma is home to at least 12 species of cicadas, one of which is a periodical cicada whose life cycle is an impressive 17 years, the longest life cycle of any known insect. Most periodical cicadas in Oklahoma belong to what biologists call brood IV and were active in 1947, 1964, 1981, 1998, 2015 and will be back in 2032.
Garden tips
·        Fertilization of warm-season grasses can continue if water is present for growth. Do not fertilize Bermuda or zoysia lawns after the end of August. Do not fertilize fescue lawns until it cools off in September.
·        Establishment of warm-season grasses, such as Bermuda and zoysia, by sodding or sprigging should be completed by the end of July to ensure the least risk of winterkill.
·        Mowing heights for cool-season turf grasses should be at 3 inches during hot, dry summer months. Gradually raise mowing height of Bermuda grass lawns from 1½ to 2 inches.
·        Cucumbers may be bitter this time of year and vines quit producing. This is due to the heat. If you are able to get the vines through the summer, after it cools, they will be fertile again and the taste of the cucumbers will improve.

Tuesday, August 1, 2017 0 comments By: Jack Downer

Crapemyrtle Bark Scale

Crapemyrtle Bark Scale

Allen Robinson: Ask a Master Gardener
Tuesday, August 1, 2017
Q: I have white spots that turn to a blackish mold on my crape myrtles. What is it and how do I get rid of it? Tricia, Tulsa.
A: We addressed this issue in this column last year, but some of the recommendations made by OSU regarding control have changed. The current recommendations come from Dr. Eric Rebek, state extension specialist for horticultural insects.
It is an insect pest that is called crape myrtle bark scale. This insect is relatively new to our area but has become fairly prevalent. It came to the U.S. from Asia and first appeared in north-central Texas in 2004. It has subsequently spread northward into the Tulsa area from nursery stock and other sources of imported crape myrtles. This is the reason one should always inspect nursery crape myrtles for scale insect before purchase.
Like other scales, the life cycle begins with either the female scale or eggs overwintering on the crape myrtle under loose bark. When the eggs hatch, small mobile “crawlers” are produced, which migrate on the plant and may be spread to other crape myrtles by wind or birds. There may be two to three generations produced per year depending on temperatures.
Once the female is fully developed, she mates and attaches to the stems and trunks of the crape myrtle, where she remains fixed and lays eggs for the next generation. She dies shortly thereafter, but the eggs survive under her covering until they hatch.
As the scales feed, they release a liquid called “honeydew.” This is similar to the behavior of aphids. The sugars in honeydew may support the growth of a fungus called “sooty mold.” This overgrowth produces large black patches on the bark of the crape myrtle. The mold is unsightly and creates a reduction in aesthetic quality, but it is not significant in terms of the plant’s health.
Garden tips

·        Divide and replant crowded hybrid iris (bearded iris) after flowering until August. When planting, take care not to plant the rhizomes too deeply. Cover them with an inch of soil or less. Do not mulch iris
·        Water all plants deeply and early in the morning. Most plants need approximately 1 to 2 inches of water per week. Rather than watering daily, water less often and more deeply.

·        Some trees such as sycamores and river birches lose large numbers of leaves in the heat of summer. Trees do this to reduce water loss from their leaves. It is a coping action by the tree; it is not dying.

Tuesday, July 25, 2017 0 comments By: Jack Downer

Watering Lawns in Summer

Watering Lawns in Summer
Tom Ingram: Ask A Master Gardener
Tuesday, July 25, 2017
Q: It’s so hot outside. How do I know how much I should be watering my lawn? E.K.
A: If your lawn is Bermuda grass, it needs about 1 inch of water per week this time of year, while fescue needs about double that or 2 inches of water per week. This answer usually leads to another question: How long do I run my sprinkler? The answer to that question necessitates you doing what we call a “simple irrigation audit.”
For a simple irrigation audit, you are going to need nine collection cups, pen, paper and a calculator (at least most of us will need a calculator). Collection cups can typically be purchased from an irrigation supply store or you can use clean metal cans that might previously have contained tuna, cat food or perhaps tomato paste. Using the same type of can for all your collection cups will make your data more reliable.
If you choose cans, you can use a ruler and a fine-tip permanent marker to mark the outside of the cans in ¼-inch increments. Or you can just measure the collected water by sticking a ruler directly into each collection can.
To collect your measurements, locate your nine collection cans about 8 feet apart in something close to a 16-by-16-foot grid.
Next, let your sprinkler run over your collection grid for 20 minutes. After the collection period is over, measure the amount of water in each of your collection cups, add up the total amount collected (calculator time) and divide the total by nine because you were using nine collection cans. This will give you an average amount of water your collection grid area received in 20 minutes.
So let’s assume your average measured amount was ½ inch. This means for every 20 minutes your sprinkler system runs, your turf will be receiving half of an inch of water. If you have Bermuda grass, which needs 1 inch of water per week, you are going to need to water 40 minutes per week. You can split this up into two watering sessions per week of 20 minutes each.
If you have a fescue lawn, which needs 2 inches of water per week, the math says you would need 80 minutes per week, which can be split up into two watering sessions of 40 minutes each.
Garden tips
  • Spider mites are a difficult pest to deal with, and they love hot, dry and dusty weather. One of their favorite targets are tomatoes, where they cause a stippling or sandblasted appearance on the leaves. They are small but may be seen if you tap a leaf over a sheet of white paper and look for moving dots. Treat with jets of water to wash them off and use either horticultural soap or oil according to directions. Neem oil is a good choice for a safe organic insecticide. If you use an insecticide of any sort, it is best to spray  early or late in the day, when honeybees are in their hive.
  • Tomato growers are aware that fruit production usually stops in the heat of summer. Most tomato pollen becomes infertile and blossoms drop off when night temperatures are above 70 degrees and daytime is above 92 degrees for a few days. This also occurs in peppers, some varieties of beans and other vegetables. As it cools in late summer, fertility returns. If your tomatoes are too tall and gangly, you may cut them back a third. New growth and fertile blossoms will develop when it cools in fall.

Tuesday, July 18, 2017 0 comments By: Jack Downer

Mulch Benefits all Gardens in Many Ways

Many Benefits of Mulch in Your Garden
Brian Jervis: Ask A Master Gardener
Tuesday, July 18, 2017

Q: I’ve heard a lot of suggestions about using mulch in my garden. Is it really worth the effort? A.M., Tulsa
A: Mulching garden soil is not only worth the effort, but also for a variety of reasons is probably the most beneficial cultural practice you can engage in to help your plants, vegetables, trees and shrubs achieve their full potential.
First of all, mulch can greatly decrease the amount of time you need to spend weeding your garden, which all of us would agree is a plus. But, in addition to less time weeding, less weeding means less chance of damaging plant roots through cultivation and weed removal.
Mulch also increases water absorption and reduces evaporation of moisture from the soil. With a good layer of mulch, we don’t need to water as often, and the water we use is put to more efficient use. This mulch layer also helps protect our plants from soil-borne diseases by reducing splashing from rain and watering.
Regulation of soil temperature during our hot Oklahoma summers is another valuable reason to add mulch to our gardens. Research has shown that nonmulched garden soil at a depth of 1 inch can vary in temperature by as much as 40 degrees during an average summer day, reaching temperatures of close to 120 degrees. Adding a layer of mulch can reduce that temperature increase by approximately 30 degrees, to a high of about 90 degrees. Reducing these extreme variations in daily soil temperature is beneficial to plant root systems.
Oklahoma soils tend to be low in organic matter, so we recommend organic mulches that can be incorporated into the soil at the close of each gardening season. Examples of organic mulching materials would include bark chips, compost, grass clippings, pine needles, sawdust and straw. Shredded leaves from the previous season’s yard cleanup also make great mulch, and you can’t beat the price.
Mulches such as sawdust or wood shavings have high carbon to nitrogen ratios that can cause them to leach nitrogen from the soil as they decompose. To compensate for this, nitrogen fertilizers should be increased by about one-fourth.
We generally recommend a mulch layer of between 2-4 inches, but the depth of mulch depends on the texture of the mulch you will be using. For example, if you were to use sawdust, peat moss, or cotton seed hulls, an appropriate mulch depth would be 1 inch because these are fairly dense mulches. However, if you were to use straw, hay, or other more coarse materials, you may need 4 to 8 inches for an appropriate mulch cover.
Mulching your garden may take a little effort, but your efforts will be rewarded with a more beautiful, productive and healthy garden.
Garden tips
·        When watering your lawn, ornamentals or vegetables, always do so in the morning, if possible. If watered in the evening, plants will go into the night still being moist. Most disease-causing organisms need moisture, and because they grow best at night, leaving leaves wet in the evening will promote many plant diseases.
·        Bulb onions are ready to harvest when the tops fall over. They should be removed and allowed to dry in a well-ventilated, shaded area. After the tops are completely dry, they may be stored in a cool, dry area.
·        Tall, spindly tomato plants with scarce fruit are usually due to either too much nitrogen fertilizer or too much shade.

Tuesday, July 11, 2017 0 comments By: Jack Downer

Consider A New Experience with an Old Technique--Keyhole Gardening

Unique Keyhole Gardening Explained
Allan Robinson: Ask A Master Gardener
Tuesday, July 11, 2017
Q: Over the years, I have heard the term “keyhole gardening” from time to time but don’t know anything about it. Is it better than regular gardening? Tom A., Jenks
A: As Oklahoma summers continue to get hotter and drier, gardeners are looking for ways to prolong the growing season while responsibly maintaining natural resources. Keyhole gardens may just be the answer by providing several advantages to conventional gardening, such as simple construction, soil enrichment, moisture retention, labor savings and extended vegetable production.
Originally developed for use by the chronically ill in third-world countries, keyhole gardens have proven to be an effective way to grow vegetables year round in moderate climates, semi-arid environments and locations with poor soil because they are constructed in such a way as to warm, nourish and retain moisture in the soil.
This type of garden has helped many populations vulnerable to hunger and food insecurity improve resiliency to shocks such as drought. Because Oklahoma has experienced semi-arid environmental conditions in recent years, coupled with the fact that our horticultural population is living longer and wanting to garden longer, keyhole gardens may very well have a natural place in our area as well.
The name comes from its original design as a relatively small round garden with a low outer wall and a space in the middle to allow a person (especially those who are physically weak or have a disability) to work the garden with minimal effort. The raised bed is surrounded by stones or equivalent material, literally of any type. Inside, the walls are built-up of layers of rapidly decomposing organic material that serve the dual purpose of continually adding nutrients to the soil and retaining moisture, making it much more productive than a conventional garden, even in cold and dry winter months.
Once built, the garden requires little ongoing maintenance; it does most of the work. Also, few additional inputs, such as fertilizer, are required.
Construction of a keyhole garden is rather simple and fun and promotes the use of inexpensive and locally available resources. You can even get your kids involved.
The outer wall can be constructed of anything resilient (brick, stone, wood, hard plastic, old tires, etc.). Internal materials include rocks and a combination of organic materials, such as small tree branches, loose twigs, wood chips, cardboard, newspaper, grass clippings, green or brown leaves, manure, compost and soil. The typical garden is only 6-7 feet in diameter.

Garden tips
·        For all your plants, ornamental or vegetable, mulching and correct watering are keys to surviving the heat of the summer. Mulch conserves water and reduces ground temperature.
·        Fescue lawns need 2 inches of water per week to survive summer; Bermuda grass needs about half that amount. Watering less frequently and more deeply is better than daily shallow watering.
·        Brown patch disease of fescue lawns is appearing now, related to excessive rains, heat and high humidity. Wet grass leaves promote the disease. Therefore, if you water in the mornings, allowing the leaves to dry during the day, there will be less likelihood of infections. Fungicides are available, but OSU feels the fungicides available to homeowners are not nearly as effective as those available to professional licensed applicators. None of these chemicals will cure existing infections; they only prevent new disease at best.

Tuesday, July 4, 2017 0 comments By: Jack Downer

Plant Fall Vegetables Now

Time for Fall Vegetable Garden is Now

Tom Ingram: Ask a Master Gardener
Tuesday, July 4, 2017
Q: I want to try a fall vegetable garden this year. What does well here in Oklahoma and when do I plant? N.J., Tulsa
A: For those of us who love the taste of fresh fruits and vegetables, gardening is a year-round activity. The fall gardening season, which begins around July 15, can actually produce some of the tastiest garden vegetables in northeast Oklahoma, as we typically have warm sunny days followed by cool nights. Under these conditions, plant metabolism slows down, which helps produce high-quality and tasty vegetables.
Vegetables grown in fall gardens can be divided into two categories: tender vegetables, which need to be harvested before the frost, and semi-hardy vegetables that can continue to grow and be harvested through several frosts.
Examples of tender vegetables would be beans (bush, pole, lima), cilantro, corn, cucumber, eggplant, pepper, pumpkin, squash and tomatoes. Semi-hardy vegetables would include beets, broccoli, cabbage, carrots, potatoes, kale, lettuce, peas, radish, spinach and swiss chard.
The brutally hot temperatures we often have in July and August demand we pay special attention to any vegetables we intend to direct seed in our fall gardens. As a rule, seeds should be planted no deeper than three times the diameter of the seed. With small seeds, such as carrots, this would mean planting no more than 1/4-inch deep. At these depths, hot soil temperatures will discourage germination. Supplemental watering or perhaps shade cloths will be needed to reduce soil temperatures so germination can occur.
The good news is many of our fall vegetables can be started from seed indoors, which helps us avoid having to deal with the soil temperature issue. Plants that perform well as transplants include cucumbers, squash, peppers, pumpkins and tomatoes. Before moving transplants into the garden, they should be conditioned or toughened by reducing watering and exposing them to full sunlight in limited amounts.
If space allows, potatoes are also a wonderful fall garden crop. Seed potatoes need to go in the ground the first two weeks of August to complete growing before the first freeze.
The first of September is the time to plant garlic, leeks and onions, as they will continue to grow through the winter for a harvest in late spring the following year.
We have several fact sheets from OSU, which not only provide you with the planting dates for fall crops but also contain recommended varieties of vegetables that can be grown successfully in Oklahoma. Just give us a call, drop by our office, or check our website, tulsamastergardeners.org. We are here to help.
You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Help Line at 918-746-3701, dropping by our Diagnostic Center at 4116 E. 15th Street, or by emailing us at mg@tulsamastergardeners.org.

Garden tips
  • Vigorous, unwanted limbs should be removed or shortened on new trees. Watch for forks in the main trunk and remove the least desirable trunk as soon as it is noticed.
  • Most varieties of mums are more productive if “pinched back” now. Either pinch off with fingers or cut to remove an inch or so of limb tips above a leaf. This results in the growth of new limbs and a fuller plant. Do not pinch after mid-July or it will interfere with fall blooming.
  • Watch for tiny, sap-sucking insects called aphids on roses, perennial flowers, shrubs and vegetables (especially tomatoes). They produce a sticky substance called “honeydew.” Many can be dislodged with a hard spray from your garden hose, or two applications of insecticidal soap will usually greatly reduce any aphid damage to your plants.
  • Crape myrtles are one of the few shrubs that should be planted in the middle of summer. Growth of new roots of these plants occurs best with summer soil temperatures.