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 (tulsamastergardeners.org, 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.

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.

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 tulsamastergardeners.org. In that same section of the website, you will find additional fact sheets on growing conditions, pests and diseases, which are helpful.

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.

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.

Master Gardner Web Site

Master Gardner’s New Informative Web Site

Tom Ingram: Ask a Master Gardener

Tuesday, January 09, 2018

Q: What resources or suggestions do you have for those of us starting to plan for our gardens this year? — LK

A: Because it’s so cold and not much fun to be outside, this is a great time to begin making your gardening plans for the year.

One of the first things you can do is review your experiences from previous years. What worked? Why did it work? What didn’t work? Why didn’t it work? What do I want to do different this year?

If you are growing vegetable crops; which crops prospered? Which ones struggled? Which pests caused the most trouble? How can I better control them? Did my garden take too much of my time? Should I make some adjustments in how I water and care for my garden?

You get the idea.

One of the things we hope will become an even more valuable resource for you than it was in the past is the new Tulsa Master Gardener website (tulsamastergardener.org). We’ve spent the past few months updating the interface to be more user-friendly and have uploaded an abundance of gardening resources to help you become a more successful gardener.

In our “Lawn & Garden Help” section, you will find information on a variety of topics, such as general landscaping, flowers, trees and shrubs, soil, vegetables, fruits, nuts, berries, insects and butterfly gardens. You will also find sections on organic and Earth kind practices, types of gardens, fertilizers and pesticides, pruning, composting and water conservation, etc.

If your plans for the year include a vegetable garden, we have information and videos on which varieties do well in our area, the best times to plant, garden layouts and how to plant tomatoes etc. If your plans include flowers, we have recommendations for annuals or perennials that do well in our area.

There is a lot of information available on the internet about gardening, and it is sometimes hard to determine if the advice or suggestion is appropriate for our area. On our site, you will know the information you read or the instructional videos you watch will be university-based information appropriate for the Tulsa County gardening community.

However, our website is not the only way we can help you prepare for this New Year. Our Diagnostic Center is staffed from 9 a.m. to 4 p.m. Monday-Friday with Master Gardeners who would love to share what they know about gardening. You can call us or email your questions via the information below. We hope you have a great garden this year and would love to help.

Garden tips

• Ornamental perennial grasses, such as pampas grass, may be cut back to 4-6 inches anytime in winter. However, because of winter attractiveness, most gardeners choose to wait until early spring to cut them back. All of the dead tops of these grasses should be removed by early spring, allowing sun to get to new growth.
• Liriope or "monkey grass" — which is not a grass but in the lily family — stays green year-round; it also benefits from trimming to 2-3 inches before new growth begins in spring. Liriope and all ornamental grasses will benefit from nitrogen fertilizer in spring when pruned.
• Prune fruit trees in January, February and March. OSU has a good fact sheet on pruning fruit trees, "Annual Pruning of Fruit Trees." You can find this fact sheet in the “Hot Topics” section of our website at tulsamastergardeners.org.

Options for Old Christmas Trees After the Holidays

Options for Old Christmas Trees After the Holidays

Brian Jervis: Ask a Master Gardener

Tuesday, January 02, 2018

Q: Now that the holidays are winding down, what options do I have to deal with the disposal of my live-cut Christmas tree? Bob W., Tulsa

A: There are several options for disposal of your live-cut tree after the holidays. Some are more environmentally friendly than others. Most options involve removing all of the ornaments, tinsel and flocking (if possible) before use.

The best option is to trim the smaller branches from your tree and place them in the garden as mulch. They will decay over time and you will reap not only the benefits of mulch but also the nutrients that it adds back to the soil. These limbs also may be added to your compost pile as a source of green material to help balance the brown material such as leaves. Both green (nitrogen source) and brown (carbon source) are needed for the microbes that break down the material. The larger limbs and stems must be used elsewhere.

For the fisherman, sinking a bundle of evergreen trees creates a “hot-spot” or “magnet” in your favorite fishing hole. Crappies love them! The whole tree may be added, usually with others that are tied together, weighted with a concrete block and dropped into your favorite spot, if allowed.

Another option is to use the old tree as a temporary winter bird refuge, sanctuary and feeding station. The fronds of needles make a good temporary shelter from wind and predators. Treats such as peanut butter, suet and seed mixtures can be added as winter food for the birds.

The last option before placing the tree at curbside collection is to take it to the city of Tulsa’s Green Waste Site, located at 2100 N. 145th East Ave. This site is open seven days a week, 7:30 a.m. to 5 p.m., excluding city holidays. Only green waste is accepted, such as trees, limbs and leaves. All are shredded for mulch. Nonorganic material, such as Christmas decorations, lights,

The waste site produces huge amounts of mulch that is available to anyone. There may even be a machine to help load your truck. Wood that can be split for firewood is often obtainable, as well. There is no charge for these services for Tulsans. You must have a valid driver’s license or a utility bill showing a Tulsa address; otherwise, there is a small fee. It is possible to take a load of neighborhood trees to the site and perhaps come home with a load of free mulch and/or free firewood.

Lastly, the city of Tulsa curbside pickup service will collect trees. In December and January, residents may put trees at the curb on their primary collection day. All decorations must be removed and trees need to be cut into 4-foot sections to fit into the hopper of the refuse trucks. This collection is not for artificial trees, which need to go in the gray trash cart. The live trees are not actually recycled but, instead, are incinerated along with the other green waste collected in Tulsa.

Garden tips

• Any green weed in dormant (brown) Bermuda lawns may now be sprayed with glyphosate, found in Roundup and many others. This will kill anything green but will not hurt the Bermuda. Glyphosate cannot be used on dormant zoysia grass or tall fescue lawns at any time.
• Control overwintering insects on deciduous trees or shrubs with horticultural oil sprays in dormant concentrations applied when the temperature is above 40 degrees in late fall and winter. Do not use “dormant” oils on evergreens.
• Make sure indoor plants are receiving enough light; set up an indoor fluorescent plant light.
• Till garden plots without a cover crop to further expose garden pests to harsh winter conditions.
• Visit the Master Gardeners office at the OSU Tulsa County Extension Building to obtain gardening fact sheets for the upcoming gardening season. The office is located at 4116 E. 15th St.