Sunday, May 12, 2019 0 comments By: Ask A Master Gardener

Common Problems When Growing Tomatoes and Suggested Solutions

Problems May Occur When Growing Tomatoes
Allen Robinson: Ask A Master Gardener
Sunday, May 12, 2019
Q: My family loves to eat fresh tomatoes off the vine, but I hear that growing tomatoes around here is a challenge. Can you tell me why it is difficult to grow them here and what I can do about it? Stacy H., Tulsa
A: You are certainly not alone both when it comes to loving tomatoes fresh off the vine as well as having trouble growing them in northeast Oklahoma.
One of the most common issues is known as “blossom drop,” which occurs from incomplete pollination. Weather is the chief cause of inadequate pollination in garden-grown tomatoes, with the most important factor being temperature. Effective pollination stops occurring once night temperatures are consistently over 75 degrees and/or when daytime temperatures are consistently over 92 degrees — especially if it is windy. Too much rain or too high or low humidity are additional weather factors which reduce pollen fertility. Also, overapplication of nitrogen fertilizer leads to blossom drop as well as tall, lanky plants and other diseases.
The solution to this is to plant very disease/pest resistant and healthy plants as soon as possible after the last frost has occurred. Then, pick the fruit as soon as it turns pink and let it continue to ripen indoors. Do not let it sit on the vine until it becomes overly ripened and soft.
Another common issue is called “blossom end rot,” where the fruit develops blemishes on the blossom end of the fruit. This is caused by a calcium deficiency in the plant when the fruit is young. Overwatering, either from nature or the gardener, is the most common cause rather than the lack of calcium in the soil. Keep the soil evenly damp as much as possible.
Skin splitting, called “cracking”, is also caused by plants going from too little to too much water. Be consistent about watering. Mulch plants to provide consistent moisture and temperature at the root level. Be careful to not mulch directly against the plant trunk as it can lead to diseases.
Speaking of diseases, avoid splashing soil on the plant and onto tomato fruits, as this carries related fungi and bacterial diseases. Instead, use either a soaker hose or drip irrigation system, or carefully water at the base of the plants. Avoid damaging tender roots by not hoeing too deeply or too closely to the plants.
In addition, there are several pests that love to live off the stems and leaves of tomato plants. For a listing of pests and how best to battle them, go online to and search for OSU Fact Sheet EPP-7313 (Home Vegetable Garden Insect Pest Control).
Experts will say that the best weed control in a lawn is to simply grow a healthy, thick lawn which tends to crowd out weeds. The same is true for vegetables. Look for high quality varieties at reputable nurseries around town and ask which varieties are the most disease resistant. There are many varieties available.
Tulsa’s climate is a challenge to growing tomatoes in the summer. But, with a little attention to the details, you can have very good success. And, remember, there’s always fall.

 Garden Tips

 Don’t spray insecticides during fruit tree bloom or pollination may be affected. Disease sprays can continue according to schedule and label directions.
 Mowing of warm-season lawns can begin now. Cutting height for bermudagrass and zoysia grass should be 1 to 1½ inches high, and buffalograss 1½ to 3 inches high.
 Harden off transplants outside in partial protection from sun and wind prior to planting.
• Let spring flowering bulb foliage remain as long as possible before removing it. That will allow the energy from the leaf to flow back into the bulb for flower production next year.
• Prune roses just before growth starts and begin a regular disease spray program as the foliage appears on susceptible varieties

Sunday, April 14, 2019 0 comments By: Ask A Master Gardener

Crapemyrtle Bark Scale Insect Control

Crapemyrtle Bark Scale Insect
Brian Jarvis: Ask a Master Gardener
Sunday, April 14, 2019
Q: I have white spots that turn to a blackish mold on my crapemyrtles. 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 Crapemyrtle Bark Scale. This insect is relatively new to our area but has become 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 crapemyrtles. This is the reason one should always inspect nursery crapemyrtles for scale insect before purchase.
Like other scales, the life cycle begins with either the female scale or eggs overwintering on the crapemyrtle under loose bark. When the eggs hatch, small mobile “crawlers” are produced, which migrate on the plant and may be spread to other crapemyrtles 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 crapemyrtle, 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 like 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 crapemyrtle. The mold is unsightly, which creates a reduction in aesthetic quality, but it is not significant in terms of the plant’s health.
This pest is easy to identify because it is the only scale insect to infest crapemyrtles. The adult female is usually about 2mm long and has a distinctive gray-white felt-like covering. When one of the females is crushed, a pink blood-like fluid is released.
The current recommendations for control are removal by hand and the use of winter dormant oils. Scrub down the trunk of the crapemyrtle with a mild solution of dish soap and water using a long-handled brush to remove the scale and sooty mold. This method is very effective. Another recommended treatment is to spray the trunks of the trees with dormant oil in late winter. Winter dormant oil spray is a stronger concentration of the petroleum-based oil that is used in summer. Neem oil, while useful in other applications, will not be effective for this scale in winter.
Previously, systemic insecticides in the neonicotinoid family were recommended. These chemicals enter into the circulation of plants and kill the pest when they feed on the sap. They have been shown to be effective against crapemyrtle bark scale but are no longer recommended. The reason for the change in policy is the concern that these insecticides enter the blossoms of crapemyrtles and would be harmful to bees and other pollinating insects.
Garden tips 

• Don’t spray insecticides during fruit tree bloom or pollination may be affected. Disease sprays can continue according to schedule and label directions.
• Mowing of warm-season lawns can begin now. Cutting height for bermudagrass and zoysia grass should be 1 to 1½ inches high, and buffalograss 1½ to 3 inches high.
• Harden off transplants outside in partial protection from sun and wind prior to planting.
• Let spring flowering bulb foliage remain as long as possible before removing it. That will allow the energy from the leaf to flow back into the bulb for flower production next year.
• Prune roses just before growth starts and begin a regular disease spray program as the foliage appears on susceptible varieties.

Sunday, March 31, 2019 0 comments By: Ask A Master Gardener

Soil Temperatures Are Key to Spring Vegetable Garden Success

Starting a Vegetable Garden in Spring
Tom Ingram: Ask a Master Gardener
Sunday, March 31, 2019
Q: It’s so nice outside, am I safe to start my vegetable garden now? CT
A: Oftentimes, people will suggest certain dates when you can plant your vegetable garden. But dates are only guidelines. To know for sure when we can plant, we must look at the weather and do a little investigation to determine soil temperature.
For example, oftentimes, people will say St. Patrick’s Day is the time to plant potatoes. There is no potato magic in St. Patrick’s Day, other than in a normal year you are probably OK planting on this day. The truth about when to plant potatoes is based on when the soil temperature is appropriate for planting.
According to the OSU Extension, soil temps need to be above 50 degrees before we plant potatoes. At the writing of this article, soil temps at a depth of 4 inches are hovering around 51 degrees. So we’re just entering optimal conditions for potato planting.
Cold soils also inhibit seed germination of some of our more popular vegetables, such as tomatoes, squash, cucumber or peppers. To overcome this challenge, it is common for gardeners to start seeds indoors so the plants will be ready to go outside when it warms up.
If you have been to any of the garden centers in northeast Oklahoma recently, you will have noticed racks of seeds and seed starting supplies. Many of us have already gotten our seeds started and can’t wait to get them out in the sun. But if we move them outside too early, we run the risk of a late freeze damaging our fragile new plants. In northeast Oklahoma, we typically say we should be safe after April 15, which is still a couple of weeks away. But it’s not unusual for us to have a late freeze. Last year, we had one night with a low of 28 degrees the first week of April, so if you jump the gun, be ready to spend some time covering your plants.
Sometimes, talking about the need to find out what your soil temperature is at various depths can be a little intimidating. But don’t let that scare you off. In Oklahoma, we have a wonderful resource called the Mesonet. The Mesonet is a joint project between OU and OSU with at least one weather monitoring station in each county. You can visit for an abundance of weather information, including rainfall and soil temperatures.
For more information on starting and growing vegetables, visit the “hot topics” section on our home page to find a link that will take you to an abundance of information to help you be a more successful vegetable gardener.
Garden tips
  • Our annual spring educational Lunch & Learn classes at the Tulsa Central Library downtown have begun.
  • One of our most anticipated events is currently underway: The Master Gardener Plant Sale. You can choose from more than 200 plants, including annuals, perennials, grasses, herbs, tomatoes, succulents and stepables.
To find out more information on any of these and other opportunities, visit our website at

Sunday, March 17, 2019 0 comments By: Ask A Master Gardener

Oklahoma Proven Selections for 2019

Oklahoma Proven Selections for 2019
Allen Robinson: Ask a Master Gardener
Sunday, March 17, 2019
Q: Given our erratic weather patterns, is there a good way to know what plants, trees and shrubs grow well in our area? Sam R., Tulsa
Rattlesnake Master
MG Demo Garden
A: This is a good question that many people think about. And it’s a very reasonable request given the amount of labor involved in planting, as well as the cost of landscaping products these days. So wouldn’t it be nice if someone had already done the research on which plants do best in our neck of the woods? And also tell us where to plant them so they have the highest chance of success? Well, they have!
It’s called the Oklahoma Proven Program. Oklahoma Proven is an annual plant evaluation and marketing program coordinated by the Department of Horticulture and Landscape Architecture at Oklahoma State University. Designed to help consumers select the best plants for Oklahoma gardens, these plants are tolerant of the varied and difficult environmental conditions found throughout Oklahoma.
Every year, an annual, a perennial, a shrub and a tree are selected. The selections for 2019 are:
Annual: Star Flower (Graffiti® series) grows to 16 inches high and 12 inches wide, making it a great plant for containers or in a flower bed. They are very heat-tolerant, drought-resistant, make great cut-flowers and attract butterflies and hummingbirds throughout the summer months. Like all Pentas, Graffiti® prefers sun/heat, dry soil with good drainage but not too rich.
Perennial: Rattlesnake Master is a native species to the tallgrass prairies. Leaves are parallel-veined, bristly-edged and sword-shaped, with medium green leaves (up to 3 feet long) resembling those of yucca. Flowers are greenish-white and tightly packed into globular, 1-inch diameter heads resembling thistles. It prefers dry, sandy soils and is best left undisturbed once established. Perfect for a xeriscape garden, perennial border or native garden. Group plants in naturalized areas for the best effect.
Shrub: Flowering Quince (Double Take™ series) are hardy, deciduous shrubs reaching 4 to 5 feet high and as wide. It produces a profusion of early spring double flowers that resemble camellias. A thorn-less shrub with bold 2-inch double flowers, it comes in colors of scarlet, orange, pink and peach. Does not produce fruit. Very drought tolerant. If needed, prune lightly after it blooms in spring.
Tree: Limber Pine (“Vanderwolf’s Pyramid”) is an evergreen tree with a pyramidal habit that typically grows 2 to 30 feet tall and 10 to 15 feet wide. It is noted for its closely spaced, twisted, silvery blue-green needles. Being native to North America, it is an adaptable, low-maintenance tree with few problems, including being resistant to pine wilt disease.
Note: All of these plants do well in the Tulsa metropolitan area whose USDA Hardiness Zone is 7A (average low temperature of 0 to 5 degrees).
The Oklahoma Proven program has been in existence since 1999. The best part is that you can find every year’s selection back to 1999 online at
Remember that all plants need special attention during the establishment phase or during periods of environmental extremes. So be sure to give them some TLC until they get established. Then, watch them succeed!
While nothing in nature is guaranteed, you can significantly improve your odds by choosing Oklahoma Proven varieties.
Garden tips
• Remove flowers from spring-blooming bulbs after blooming is completed. This will allow the plant to direct its energy into its bulb for next year's blooms, rather than producing seeds. But allow foliage of these bulb plants to die and turn brown naturally before removal. As long as the leaves are green, they are storing energy for the following year. Fertilize them at the time of planting, in the fall or in the spring when their leaves first emerge.
• Cool-season lawns, such as bluegrass, fescue and ryegrass, may be fertilized now with the first application of the season. Usually, four applications of fertilizer are required per year in March, May, October and November. Never fertilize these lawn grasses in summer.
• Start your routine fruit tree spray schedule prior to bud break. Contact the Master Gardener office for a document outlining recommendations for all fruit tree types as they are not all the same.

Sunday, March 3, 2019 0 comments By: Ask A Master Gardener

Master Gardener’s Educational Programs Can Help You Succeed in the Garden

Master Gardener’s Educational Programs Can Help 
Brian Jervis: Ask a Master Gardener
Sunday, March 3, 2019
Q: After a few years of gardening, I am not happy with the results I am getting. How do I “up my game” so to speak? JF
A: That is a good question, and it is one experienced gardeners also deal with. We buy the plant, we do our best, and it still doesn’t thrive. Why?
There are a variety of factors that contribute to your success or failure.
 Did the plant get too much sun?
 Did the plant not get enough sun?
 Did the plant get too much water?
 Did the plant not get enough water?
 Was the soil chemistry appropriate for the plant?
 Did I fertilize properly and with the correct ingredients?
The list goes on and on, and we are not going to be able to cover the variety of variables in a single article.
But what we can do is tell you about all of the opportunities we have this spring for you that can help you become more successful.
First of all, our ever-popular Urban Gardener classes begin March 14. There are six classes on consecutive Thursday evenings where we will cover topics such as plant botany, pollination, composting, soil science, growing vegetables, pollinator gardens, shrubs and trees, and turf. These are fairly in-depth classes for beginners and those wanting to “up their game” as you said. The series costs $40 or you can sign up for individual classes for $10 each. If you are interested, you can sign up on our website.
Next, we have our Lunch & Learn classes at the Tulsa Central Library. For six Tuesdays from 12:10-12:50 p.m. starting March 26 we will have classes covering spring garden tips, tomatoes, fruit trees, pollinator gardens, seed saving and composting. Did you know the Central Library has a seed library where you can check out seeds? Find out about this and a variety of other topics in these free classes. Bring your lunch and learn from the Tulsa County Master Gardeners.
Can’t decide what plants to add to your garden this spring? Each year, we offer a huge selection of Master Gardener-approved flowers in our online plant pre-sale fundraiser. We have more than 200 annuals, perennials, herbs, tomatoes and grasses. Plus, this year we added succulents, steppables and a “sort” for pollinator plants so you can build your own pollinator garden. The shopping is easy (online) and when plant pick up day comes (April 18) you can drop by the Exchange Center at Expo Square, pick up your plants (we’ll even load them in your car for you) and shop a special selection of plants available in our one-day pop-up plant store. We will have a lot of milkweed available so you can do your part to help support the Monarch population this year.
More information is available for all these opportunities on our website:
Garden tips
  • If you had previous damage to the tips of pine tree limbs, especially non-native pines, it may be diplodia tip blight (a fungus) or Nantucket pine tip moth damage. Both are controlled with pesticides starting this month. Call the Master Gardener office at 918-746-3701 for recommendations.
  • Pre-emergent herbicide to control crabgrass should be applied by the middle of March.
  • Divide and share with friends and replant overcrowded summer- and fall-blooming perennials.

Sunday, February 17, 2019 0 comments By: Ask A Master Gardener

Use Preemergent Herbicides Now to Prevent Crabgrass this Summer

Use Preemergent Herbicides to Prevent Crabgrass
Allan Robinson: Ask Master Gardener
Sunday, February 17, 2019
Q: When is the best time to apply preemergent herbicide to help control crabgrass? Johnathan W., Tulsa
A: Preemergent herbicides are definitely helpful in preventing weed establishment. They are used in early spring (mid-February through mid-March) to prevent crabgrass and other summer weeds. They also are useful in the fall (mid-August through mid-September) to prevent winter weeds such as henbit. Many of the herbicides will need a second application in spring 60 days after the first application for complete coverage of crabgrass. The product label will indicate if this is needed.
Many people are reluctant to use herbicides of any sort for weed control. That is a reasonable choice for those who are willing to tolerate some weeds. The best preventative is to maintain a healthy, well-established lawn, as this will help prevent much of the weed invasion. A healthy, thick lawn depends on good soil, proper turf grass for the area, adequate sunlight and supplemental irrigation. Most lawns need some fertilizer, and there are organic and synthetic sources available for nutrients.
The Tulsa Master Gardener website contains several helpful lawn maintenance calendars indicating what to do, what to use and when to use it for Bermuda and fescue lawns. Specifically, see the “Turf” section of the Master Gardener website for complete details.
Master Gardeners are often asked if there are any “organic” preemergent herbicides, as opposed to commercial or “synthetic” ones. Unfortunately, while there are other organic pesticides, there is no effective organic preemergent herbicide.
Corn gluten is an organic sold as crabgrass prevention. Some reports state that if it is applied during a narrow window in spring, there may be some benefit. OSU turf grass specialists cite studies that show little benefit.
For those wishing to use a synthetic pre-emergent herbicide, OSU has some recommendations. While there are several varieties of preemergents available on the market to prevent weeds, especially crabgrass, OSU feels that one of the many commercial brands containing the chemicals dithiopyr, pendimethalin or prodiamine are good choices. These preemergents cost a bit more than other types but last a lot longer and, in many cases, can kill crabgrass and other weeds after they have sprouted.
The labeled directions of all such products must be followed. These herbicides usually come on a dry particle such as fertilizer or other inert material. They may also be found less often as liquids. They must be washed onto the soil with at least ½ inch of water after application. After washed onto the soil, they form a barrier for weed prevention, which may last for months if undisturbed.
One of the benefits of these three products is that they are not soluble in water and, thus, do not leach into groundwater or spread from where they are applied. They are broken down in nature by sunlight and soil microorganisms.
Garden tips

• Now is a good time to cut back your perennial ornamental grasses, such as Pampas grass. Cut back to remove the dead grass, but avoid damaging new buds and early green growth at the base.
• Begin planting blackberries, raspberries, strawberries, grapes, asparagus and other perennial garden crops this month.
• Most bare-rooted trees and shrubs should be planted in February or March. The roots of these plants are easily damaged and should never be left exposed to air. Plant them at the same depth as in the nursery and make sure good root and soil contact is made by gentle tamping and irrigation after planting.
• Finish pruning shade trees, summer-flowering shrubs and hedges. Spring-blooming shrubs, such as forsythia and azaleas, may be pruned immediately after flowering (not before). Do not top trees or prune just for the sake of pruning.
• Applying preemergent herbicides earlier rather than later may be desirable to prevent crabgrass and other summer weeds.

Sunday, February 3, 2019 0 comments By: Ask A Master Gardener

Soil Tests of Lawn and Garden Beds Are Very Helpful

How Soil Tests are Helpful
Tom Ingram: Ask a Master Gardener
Sunday, February 3, 2019
Q: I wasn’t happy with how my yard looked last year or how my vegetables grew. How much and what kind of fertilizer should I use this year? DJ
A: This is a question we get quite often. The reality is that the question, while well-intentioned, is like me calling you on the phone and asking you how much gas I should put in my car. Your first response would be, “Well how much gas do you have in your tank now and where are you going?” To answer your question, I could look at the fuel gauge and tell you I have half a tank and I just plan on running some errands. In response you could say, “Well you don’t really need gas right now, but you better fill it up at the first of the week.”
It is the same way with soil. When someone asks how much and what kind of fertilizer they should use, we need to ask some questions. Or in this case, we need to take a soil test, which is similar to looking at the gauge to see how much fuel we have.
To perform a soil test, you will need something to collect your samples with and a bucket: a trowel or a bulb planter work well. We recommend you get between 15 to 20 samples of soil from locations scattered throughout your yard. Each individual sample does not need to be large, but you should dig to a depth of about 6 inches.
Once you have your samples in a bucket, mix them up and remove any sticks or debris. From this mixture of soil, bring a representative sample to the OSU Extension office. We will only need about a sandwich bag-sized amount of soil for your test.
When we receive your soil sample, we will send it to the Soil Science Lab at Oklahoma State University for analysis, and within 2 weeks, you should receive the results. Your results will contain the levels of nitrogen, phosphorus and potassium found in your soil, along with the pH level. Included will be a recommendation on the nutrients you need to add and how much, along with recommendations on perhaps the nutrients you need to stop adding. Not only is over-application detrimental to your growing environment, but it is also a waste of money.
The test costs $10, but likely, it will be the best $10 you have ever spent on your lawn or garden. If you want to test a smaller garden or flower bed, this will require a separate test as those environments would be unique from your lawn. The same instructions would apply. So grab a bucket and let’s find out what your soil really needs.
Garden tips
  • Early February through March is the recommended time to plant strawberries. It is important to plant them in full sun and in well-drained soil. There are several types to choose from. June-bearing varieties do best in our area. They have a single crop usually early May to mid-June. Ever-bearing strawberry is another variety which fruits May to June, a few during summer and again in the fall. The quality and size of this type of strawberry plant may not be as good as June-bearing varieties. For full information about plant selection and growing tips, visit the “Hot Topics” page of our website.
  • Mid-February is a good time to begin pruning and fertilizing trees and small fruits.