Saturday, March 10, 2018 0 comments By: Jack Downer

Prune Crapemyrtles in Late Winter, But Avoid "Crapemurder"

How not to commit 'crapemurder' on your crapemyrtles this spring

Brian Jervis: Ask a Master Gardener

Saturday, March 10, 2018

Q: How and when should I prune my crapemyrtles?

A: Crapemyrtles, along with all trees and shrubs, should only be pruned for a reason. The best time to prune these and other trees and shrubs is late winter or early spring, before leafing out. An exception to this time are the spring-blooming shrubs, such as azaleas and forsythias, which should be pruned after blooming, if needed. Delaying pruning of spring-blooming plants is only to preserve the flower buds formed the previous year.
There is a common belief by many that crapemyrtles should be pruned back to an ugly set of horizontal nubs in the spring time. Nothing could be further from the truth about good crapemyrtle care. Crapemyrtles should be allowed to let nature have its way and to grow to their full height.
Some people think that blooming will be increased by drastic pruning (many horticulturists call this “crapemurder”), but Dr. Carl Whitcomb, a retired OSU professor and developer of crapemyrtle cultivars, cites evidence that blooming is less, not more, with drastic pruning. Light pruning of endmost 12-18 inches, back to a lower limb, can increase numbers of blossoms. However, these plants were engineered by nature to bloom profusely without this type of pruning. In summer, one can promote a second wave of blossoming by pruning off old blossoms after they fade.
Reasons to prune crapemyrtles are to confine it to the space available or to improve the shrub’s shape and structure. Removal of dead or diseased limbs and elimination of internal crossing branches should be done anytime.
For those plants that are too big for their space, rather than trimming them back each year, consider removal and planting one of the smaller crapemyrtle cultivars. There are many sizes available, ranging from 18 inches to 25 or more feet when mature.
One question that sometimes arises relates to the seed pods left over in fall after blooming is completed. The plant will remove them naturally as they have been doing for thousands of years, and they need no pruning.
Another pruning suggestion one should consider with crapemyrtles concerns those plants with a multitude of trunks. These are best reduced to three to five trunks, which will not only have more curb appeal, but also will allow more energy to be directed toward further growth and blossom formation. To further improve appearance of these shrubs, consider removing the limbs from the lower third or half of the trunks.
Crapemyrtles are notorious for sending up shoots or sprouts from the base of the plants, especially in the spring. These should be removed by pulling off if able, or clipping close to the ground, if needed.
We have an advantage over our northern neighbors in being able to grow these magnificent plants, which are the mainstay of color in Tulsa during the summer. They deserve the best care we can give them, they should not be subjected to “crapemurder.”

Garden tips

  • Now is a good time to cut back your perennial ornamental grasses, such as pampus 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. Contact Tulsa Master Gardeners at 918-746-3701 for specifics about these plants.

Sunday, March 4, 2018 0 comments By: Jack Downer

Guidelines for Planting Vegetables in Springtime

Spring Vegetable Planting
Tom Ingram: Ask a Master Gardener
Sunday, March 04, 2018
Q: When can I start my vegetable garden? MA
A: Oftentimes, people will suggest certain dates when you can plant your vegetable garden. But dates are only guidelines. To know for sure when you 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 when 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 is based on the best soil temperature for planting potatoes.
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 are hovering around 46 degrees. So, we are getting close, and if the weather continues on as we expect, we will likely have a soil temp above 50 degrees by St. Patrick’s Day. But give us a few warm days and an expectation that spring is on the way and we could plant them sooner.
Peppers are easy to grow in Oklahoma and have the benefit of being a versatile crop. However, peppers are sensitive to temperature. Air temperatures of below 60 degrees or above 90 degrees can prevent fruit set, which can limit the growing window in Oklahoma.
So, how do Oklahoma gardeners get around this? Because cold soils do not encourage germination, it is common for gardeners to start seeds indoors so they will be ready to go 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 these little ones in the ground.
But the time to plant these transplants still depends on soil temperature and when the danger of a freeze has passed. In northeast Oklahoma, we typically say that date is April 15. Many of us have a hard time waiting that long and tend to plant before that date. However, if you do, you should be ready to cover your plants if a late-season snow arrives.
Now, you may be saying, all this talk about soil temperature, how am I supposed to know that? 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. We also have an abundance of resources on our website to help you grow better vegetables.
Garden tips
  • Our yearly Urban Gardener classes begin March 15. Topics include plant botany, soil, growing fruits and vegetables, flowers, trees and shrubs, and turf.
  • We will also be conducting our educational Lunch & Learn classes at the Tulsa Central Library downtown beginning March 20.
  • One of our most anticipated events is currently underway: The Master Gardener Plant Sale. You can choose from 211 plants including annuals, perennials, grasses, herbs and tomatoes.
  • To sign up or find out more information on any of these programs, visit our website,

Sunday, February 18, 2018 0 comments By: Jack Downer

Use Preemergent Herbicides Now to Prevent Crabgrass and Other Summer Weeds

Use Preemergent Herbicides Now to Prevent Crabgrass
Brian Jervis: Ask a Master Gardener
Sunday, February 18, 2018
Q: When should I use crabgrass preventer on the lawn? And what is suggested to use? Steve C., Tulsa
A: There are several approaches one may take concerning lawn weeds. Some people simply ignore them, while others will wish to eliminate or prevent weed growth. The most effective preventative measure is to cultivate a healthy, thick lawn, which prevents weed seed germination and crowds out existing weeds. Any additional measure you may take toward a weed-free lawn, whether it is Bermuda or fescue, includes herbicides.
Herbicides for lawns come in two categories: pre-emergent and post-emergent. The pre-emergents are applied before the weed germinates; the post-emergents are used after the weed is growing. Pre-emergents should be applied to the lawn in February or no later than March 15 to prevent crabgrass and other summer weed growth. Pre-emergents for control of winter weeds should be applied in late August up to mid-September.
Always apply according to label instructions. When applied correctly, they are effective but still may not provide 100 percent control of all crabgrass. Activation requires all products to be watered into the lawn. Watering causes the soil surface to be coated with a thin layer of the herbicide and, because they dissolve poorly in water, may last for several weeks.
Some of the more popular herbicides that you will find in the Tulsa area are (brand names with the generic names in parenthesis): Amaze (benefin+oryzalin), Balan (benefin), Barricade (prodiamine), Hi-Yield Crabgrass Control (benefin + trifluralin), Dimension (dithiopyr), Halts (pendimethalin) and Portrait (isoxaben).
Generally, the products with benefin, alone or in combination with trifluralin, have a shorter duration of activity. A second application may be needed again in 10-12 weeks for control of late germinating crabgrass and goosegrass. Barricade, Dimension and Halts all have a much longer period of control of crabgrass and may need no second application. However, if allowed on the label, a second application can be an insurance policy that is to be applied no later than the second week of May in the Tulsa area.
All of these products, except Portrait, are excellent in preventing crabgrass growth and will have some effect on controlling broad leaf weeds from seed as well. The types of broadleaf weeds controlled vary by product. Dimension, Barricade and Halts all have good activity in preventing broadleaf weeds. Portrait is unique because it is formulated for broadleaf weed control alone and has little to no effect on crabgrass.
Whatever your choice, if you do use a pre-emergent, February/March and August/September are the times for application. However, do NOT use in late summer if you plan on reseeding fescue in the fall. Pre-emergents may be used on all Tulsa lawn grasses.
If you have questions about these products or lawn care in general, the OSU Cooperative Extension has two excellent condensed information sheets on Bermuda and fescue grasses. They are available for free at the Tulsa Master Gardeners website (, under “Lawn & Garden Help”, then “Turfgrass”), as well as at the OSU Extension Office, 4116 E. 15th St. near the Tulsa Fairgrounds.
Garden tips
  • Mid-February is a good time to begin pruning and fertilizing trees and small fruits.
  • February is a good time to begin cutting 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. Contact Tulsa Master Gardeners at 918-746-3701 for specifics about these plants.

Tuesday, February 6, 2018 1 comments By: Jack Downer

Mistletoe’s History as Oklahoma's State Floral Emblem

Mistletoe’s History in Oklahoma

Tom Ingram: Ask a Master Gardener

Tuesday, February 06, 2018

Q: A few weeks back, you wrote an article about mistletoe. Isn’t mistletoe the state flower of Oklahoma? DH
A: The history of mistletoe in Oklahoma is quite a story, and the answer to your question is a resounding yes and no.
As the story goes, Oklahoma territory was to have a pavilion at the Chicago World’s Fair in 1893. The fair proposed states should consider selecting a floral emblem to represent them at the exhibit. So, even though Oklahoma was still a territory rather than a state, Rep. John Wimberly introduced a bill to the Territorial Legislature meeting in Guthrie that would identify mistletoe as the territory’s official floral emblem.
Even though a variety of flowers were considered to fulfill the honor of serving as the official floral emblem of Oklahoma territory, Wimberly argued that during the previous hard winter, no flowers could be found to put on graves. The only greenery around to serve that purpose was mistletoe, and because of this, mistletoe should be selected. His argument must have been compelling because mistletoe prevailed to become Oklahoma’s official floral emblem.
Later, before Oklahoma became a state, Bill Murray, who would later become governor of Oklahoma and be known as Alfalfa Bill Murray, lobbied to change the floral emblem from mistletoe to (you guessed it) alfalfa. He asked the question most of us have considered: Who in their right mind would designate a parasite as the state flower? His desire was for Oklahoma to be known as the Alfalfa state, which would align with the success of this crop in the area. However, his efforts were unsuccessful, and mistletoe prevailed.
Years later when Oklahoma became a state, members of the constitutional convention made it official: mistletoe would be the floral emblem of the state.
In 1986, Rep. Kelly Haney of Seminole introduced a bill that would identify the Indian Blanket as the official wildflower of the state. The bill passed, and the new symbol was celebrated at a ceremony attended by more than 20 Native American tribes. However, with some amount of apology, it was announced the lowly parasite mistletoe would remain Oklahoma’s official floral emblem.
With some degree of predictability, every few years someone would propose a change to no avail until 2004 when Gov. Brad Henry signed into law a bill making the Oklahoma Rose the official state flower of Oklahoma. However, mistletoe continues to remain our official floral emblem.
However, none of our rather unique history with mistletoe should be surprising from a state whose official vegetable is the watermelon, but that is another story.

Garden tips
  • 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. Do not top trees or prune just for the sake of pruning.
  • Dormant oil can still be applied to control overwintering insects.

Tuesday, January 30, 2018 0 comments By: Jack Downer

Prune Ornamental Grasses in Late Winter

Pruning Ornamental Grasses
Allen Robinson: Ask a Master Gardener
Tuesday, January 30, 2018
Q: When is the best time to cut down my ornamental grasses? And, I have a lot of it, so what’s the best way to prune them? Angela W., Tulsa
A: Grasses and grass-like ornamentals are great resources for gardens and landscapes. Whatever the garden need, there is likely a grass to offer a solution. They come in all sizes, from a few inches to more than 10 feet tall, and may be annual, perennial, evergreen or deciduous. The spectrum of colors, leaf patterns and textures will provide something to please most any gardener.
Many of the true grasses have intriguing fall colors and evolve to an earthy tan color for winter. So for most of them, like the large Pampas Grass, the show is not over in the wintertime. They have large decorative flowers and seed heads that catch the breeze, which adds movement and sound to the winter landscape. They not only provide interesting landscape, but also valuable shelter from the weather for birds. These seed structures can also be of value to use indoors for long-lasting floral arrangements.
For new growth to emerge in the spring, the old stems should be cut to a height of a few inches in late winter. Do this before new growth begins. If you wait too long to trim in the spring after new leaves emerge, you will remove the tops of new growth. Cutting back allows needed air and sunlight to get into the root zone and provides room for new growth. The stems on these grasses are substantial and, in many cases, can be difficult to cut. The use of a power hedge trimmer seems to be most effective for the larger grasses, such as Pampas and Zebra grass.
As for small ornamental grasses, Liriope is one of the most common grasses around but is actually not a grass at all. It is of the lily family from Asia. The many varieties available are durable and tolerant of most soils. One of their greatest assets is shade tolerance. They do well in partial to deep shade and will get sunburn in full sun.
These plants are not perennial but are evergreen and retain their usual color throughout the winter. Be aware that both tend to get a fungus called anthracnose, which causes brown spots. By the end of winter, they usually are looking a bit ragged but then predictably send up a flush of new growth in the spring, so late winter trimming is also needed.
Because the total height of these is less than a foot, lawnmowers or weed eaters are useful for removal of old growth. Cut the leaves down to 3 inches or so and discard the old leaves if they are showing any signs of fungal growth.
Pruning time is also a good time to consider dividing the grasses. This needs to be done every three to four years. Doing so will help to maintain vigor and to prevent disease in the central root area.

Garden tips
  • Begin planting blackberries, raspberries, strawberries, grapes, asparagus and other perennial garden crops in February.
  • One can continue in the month of February spot-spraying weeds in your dormant Bermuda lawn. Use a product containing glyphosate. Use when the temperature is above 50 degrees. Read the label carefully before using.
  • Tomato seeds are best planted in indoor flats around Valentine's Day for mid-April garden transplants. Should you decide to grow your own tomato transplants from seeds, consult OSU fact sheet “Growing Tomatoes in the Home Garden,” which can be found on the Tulsa Master Gardener website at In that same section of the website, you will find additional fact sheets on growing conditions, pests and diseases, which are helpful.

Tuesday, January 23, 2018 0 comments By: Jack Downer

Advantages of Raised Bed Gardening

Raised Bed Gardening
Tom Ingram: Ask a Master Gardener

Tuesday, January 23, 2018
Q: I seem to struggle with my vegetable garden each year. Would a raised-bed garden help? JL
A: Raised-bed gardens are a great option for the home gardener and also get us away from the idea of having to plant our crops in rows. The idea of planting crops in rows began with the use of a horse to help cultivate our gardens. The straight rows made plowing easier, and that practice continues today with tractors. However, for the home gardener, row gardening wastes space that could be utilized with crops.
Here are some of the benefits you will experience with a raised-bed garden:
• Higher yields — Raised beds provide you with more space for growing plants.
• Better soil — Typically, when we build new raised beds, we purchase a quality garden soil with high levels of organic matter. This strategy is much easier than working year after year to try to get your soil to the proper soil texture and nutrient balance. Not that you won’t have to work on it each year but at least you will likely be starting with a higher quality garden soil than you find in most residential yards.
• Water conservation — Plants grown together in a denser growing environment decrease water evaporation and help keep roots cooler in our hot Oklahoma summers. You also tend to use less water, as you are typically watering smaller areas.
• Less weeds — Plants that are closer to one another tend to discourage weed growth. But, in either case, mulch is always a great idea.
• Longer growing season — Soil in raised beds tends to warm up earlier in the season, extending your growing season.
• Better pest control — It’s typically easier to control pests in raised-bed gardens, as they are easier to cover with insect-screening fabric or perhaps equip to help discourage hungry rabbits and squirrels, etc.
Raised-bed gardens come in a variety of sizes, but the maximum width we usually recommend is about 4 feet, as you will want to be able to reach into your garden from either side without needing to walk in it. The height of the bed can vary greatly. A 6-inch height is fairly standard; however, you can build your beds higher if you want to be able to sit more easily to care for your garden rather than stoop or get down on your knees.
It’s also best to orient your raised-bed garden north-south with the taller plants on the north end to avoid shading the smaller plants.
Yes, raised-bed gardens are a great solution, and this is the perfect time to start planning. You can find more information about raised-bed gardening by visiting the “Hot Topics” portion of our website and clicking on “raised bed gardening.”
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 from which to choose. June-bearing varieties do best in our area. They have a single crop usually in early May to mid-June. Ever-bearing strawberry is another variety that 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, planting and care of strawberries in your garden, obtain OSU fact sheet "Growing Strawberries in the Home Garden" online or in the Master Gardener office.
  • Mid-February is a good time to begin pruning and fertilizing trees and small fruits.

Tuesday, January 16, 2018 0 comments By: Jack Downer

Pruning Hydrangeas Needs a Little Thought

Pruning Hydrangeas
Allen Robinson: Ask a Master Gardener
Tuesday, January 16, 2018
Q: I am confused as to when to prune hydrangeas. I have heard to prune in the spring, while others say the fall. Which is correct? Diane W., Owasso
A: Actually, both answers are correct, as it depends on the type of hydrangea.
First, hydrangeas generally do well with no pruning, but there are several reasons for gardeners to get out the shears. Only prune a plant when there is a reason — don’t prune simply because everyone else seems to do it. Your plant may be a candidate for pruning if it is too large or too dense, has dead or diseased limbs, or if you want to try to increase blossoming.
When to prune depends on the type of hydrangea and its blooming time. There are four species of hydrangeas commonly planted. The most popular is the Hydrangea Macrophylla (Bigleaf Hydrangea). This species is divided into Mophead and Lacecap blossom types and are usually blue to pink.
The white-blossomed Oakleaf Hydrangea (Hydrangea Quercifolia) is the next most popular. Both of these hydrangea species bloom in early summer on buds formed during the previous late summer and fall. Because spring-blooming hydrangeas bloom from buds grown during late summer and fall of the previous growing season, pruning these hydrangeas before spring will cause all the blossom buds to be lost. Instead, they should be pruned immediately after blooming and only up to early July before next year’s buds are formed.
Hydrangea Arborescens (“Annabelle” and others) and Hydrangea Paniculata (“PeeGee” and related) are less common. They have blossoms that are initially white and bloom on same-season buds formed during the summer. Prune these after summer flowering and up to early spring.
While older varieties of Macrophylla hydrangeas are only spring bloomers, some of the newer cultivars bloom in spring, as well as summer, and into the fall. The popular Endless Summer, a true Mophead, was the first of several re-blooming hydrangeas put in production in recent years. Because it is capable of blooming on old and new buds, the pruning of these after the spring or late summer flush of blossoms is acceptable. There is no true consensus for the best pruning time, as they are very forgiving.
Pruning should not be confused with dead-heading, or snipping off the spent blossoms as they occur. This can be done anytime and likely increases the number of subsequent flowers, especially in the re-blooming varieties.
It takes hydrangeas about three years to establish a good root system and, in an ideal world, it would be best not to prune during this time other than to remove dead wood or poorly placed branches. One exception is that older plants may be rejuvenated by pruning one-third of the oldest stems to the ground in late winter regardless of their blooming habits.
For more information on pruning, consult OSU fact sheet HLA-6409 on “Pruning Ornamental Trees, Shrubs and Vines,” which is available on the newly updated Tulsa Master Gardener website or at the OSU Extension Office.
Garden tips

·        Several early season vegetables are grown from seeds and planted as sprouts or transplants. Some examples are cabbage, cauliflower, broccoli, head lettuce, onions, tomatoes, peppers and eggplant. Most of these take 5-7 weeks from planting indoors until ready for transplanting into the garden. Onions take a little longer to grow.
·        Of these cabbage, cauliflower, lettuce and onion sprouts should be set out from mid-February to mid-March. Plant broccoli sprouts in March. Tomatoes, peppers and eggplants need warmth and suggested planting time is mid-April, although many people take a gamble and plant earlier, depending on the weather. Look for seeds at local gardening centers or online now.