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MANAGING BERMUDA GRASS IN HOME LAWNS

GARDEN TIPS – Written by Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA Written March 6, 2016

There are two main types of grassy weeds in home lawns, annual ones that come up from seed every year and perennial ones that persist from year to year growing from roots and runners that survive the winter cold. Controlling grassy perennial weeds in a lawn is a very difficult challenge. There are few, if any, chemicals available that will effectively kill the offending grassy perennial weed without harming the desirable lawn grasses.

One of the most hard to control perennial grassy weed is Bermudagrass. Bermudagrass is commonly planted in warmer parts of the country as a lawn and pasture grass. However, in our region it is considered a nasty aggressive and invasive weed in lawns and gardens. As a warm-season grass, it goes dormant during the cool months of winter and does not start growing actively until warmer months. It has tough wiry rhizomes (runners beneath the soil) and stolons (runners above the soil). It is sometimes confused with crabgrass because their seed heads are similar, but crabgrass is an annual that sprouts from seed every year and does not have tough persistent rhizomes or stolons.

Certain poor lawn care practices can encourage Bermudagrass. To avoid helping this dastardly weed, do not fertilize during the warmest months of the summer. This is the time of year when Bermudagrass is actively growing and fertilization at this time helps it grow even more. Abstain from frequent shallow irrigation and mowing short, practices that also promote Bermudagrass growth.

However, even the best of lawn care practices will not get rid of an existing infestation. If you can not tolerate this heinous weed taking over your lawn, you will need to consider using herbicides for management. In the last few years fenoxaprop, an herbicide, has become labeled for use by home owners for “suppression” of Bermudagrass. “Bayer Advanced Bermudagrass Control for Lawns” contains fenoxaprop.

It is important to note that suppression is the key word here. Fenoxaprop does not kill Bermudagrass outright, it only slows its growth. As noted on the label, using fenoxaprop to manage Bermudagrass involves repeated applications (every four weeks throughout active growth) over one or more years. Late application or missing just one application will significantly impair the chemical’s effectiveness. Proper timing of applications should be accompanied with lawn care practices that do not encourage Bermudagrass.

Of course, you could decide to “nuke” it and kill all the Bermuda grass along with your lawn grass so you can start over with a clean slate. However, even an application of the non-selective herbicide glyphosate (also known as Roundup, Impede, Knockout, and other trade names) is not a silver bullet. Bermudagrass is so tough that it will probably take several applications or more, spaced four weeks apart to kill this fiendish weed. (Glyphosate is should be applied when the Bermudagrass is green and actively growing.) Plus, once it appears dead and you till the ground, you should wait about two weeks or so to see if it any Bermudagrass begins to regrow and treat again if it does.

Warning! Common Bermudagrass does a good job of producing seed so even if you kill the existing perennial plants, it leaves behind plenty of seed that is viable for two years or more. If you are lucky enough to get Bermuda grass under control, it can easily re-invade the lawn from seed. Always watch for new patches starting to grow. Remember, I said perennial grassy weeds are difficult to control. In a couple of weeks we will talk about creeping bentgrass, another frustrating perennial grassy weed.

GARDEN NOTE: It is interesting to note that there are now improved hybrids of Bermudagrass available for planting lawns in the warm regions of the country. These hybrids have finer textured leaves, a darker green color, and they do not produce seed.

PERSISTENCE KEY TO CONTROLLING BERMUDA GRASS IN LANDSCAPE

written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

I recently heard a group of gardeners talking about the problem of controlling Bermudagrass in landscape beds. Calling it a problem is an understatement. Control of Bermudagrass is a colossal challenge and can’t be achieved easily. Before we talk about control, let’s talk a little about this pernicious grassy invader.

Bermudagrass didn’t come from Bermuda. This low growing, blue-green perennial grass was introduced to this country from southeast Africa in 1751 and has been used both as a forage grass for livestock and as a lawn grass in the warmer regions of the country where cool-season grasses are difficult to grow. In fact, there are cultivated varieties of Bermudagrass that don’t produce seed developed for use in these regions.

In this area, few people purposely plant Bermudagrass lawns, but end up with lawns and landscape beds invaded by this aggressive warm-season grass. Bermudagrass can propagate itself from plentiful seed that develops in late summer. Seeds stay viable in the soil for at least two years.

Bermudagrass also spreads by both tough, wiry rhizomes (root like stems in the soil) and stolons (trailing aboveground stems that can root at base of every leaf or node). Pulling or simple cultivation are not effective ways to control Bermudagrass because pieces of rhizomes or stolons left behind can grow into new plants. However, a persistent program of cultivation and withholding water over an entire season can end in success… if there are no desirable plants in the bed that will suffer from a lack of water and regular cultivation.

Many gardeners use glyphosate (such as Roundup or other brand names) in their attempts to control Bermudagrass. To be effective, glyphosate should be applied when the grass is actively growing in mid-summer. Two to four applications timed three to four weeks apart may be needed for satisfactory control of any regrowth. Perseverance is essential.

The problem with using glyphosate in landscape beds near established trees, shrubs, and perennial is that it’s “non-selective.” If glyphosate is applied to green leaves, stems, or even thin young bark it can enter these desirable plants and cause damage. I have had several plants brought into me this year that were exposed to glyphosate last summer or fall and were showing signs of herbicide injury this spring. Symptoms include stunted, distorted, and narrowed yellowing leaves along with dieback of growth. To avoid this problem, many gardeners will use a shield of cardboard between their desirable plants and the Bermuda grass when applying glyphosate.

Some gardeners have discovered that there are “selective’ herbicides that will kill perennial grasses, including Bermudagrass, but will not harm most non-grasses like trees, shrubs, roses and perennial flowers to which they are applied. The two selective grass herbicides available to home gardeners are sethoxydim ( Monterey Grass Getter) and fluazifop (Ortho Grass B-Gone). They work best in spring when the Bermudagrass runners are 4 to 6 inches long and not drought stressed. Re-treatment will usually be necessary and should be done when the regrowth reaches six inches again throughout the season.

Any of these herbicides are not a one-time “silver bullet” for control of Bermudagrass in landscape beds. Tenacity using both the non-selective glyphosate or the selective grass herbicides will be needed.

Garden Note: Many gardeners now have ornamental grasses in their landscape beds which can be damaged if exposed to these herbicides. Before using any of these products, read and follow the label directions.

Published: 7/2/2011 9:31 AM

BERMUDA GRASS CONTROL

written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

Several weeks ago I talked about crabgrass control and the right time for applying “preventers” or pre-emergent herbicides. Every spring there is always much discussion and concern about the right timing for applying these products. However, after the weather warms up and the grass you thought was crabgrass starts growing again, don’t start blaspheming the products or your application timing. It’s very likely that the crabgrass you thought you had is really Bermuda grass.

Bermuda grass is a warm season perennial grass, not an annual like crabgrass. It has a prostrate growth habit, growing along the ground by stolons (aboveground stems) that root at the nodes and by rhizomes (underground stems that can send up new shoots at each node). At this time of year, Bermuda grass looks brown and dead, but it’s really just dormant. As the weather turns warmer it will start leafing out with its gray-green leaves. In lawns, it typically forms dense patches, crowding out the desirable turf grasses planted there.

If you have lived in much warmer climates, you may not find Bermuda grass objectionable since it’s recommended for use as a lawn grass in the warmest parts of the country. Unfortunately, in our cooler climate it’s only green during the heat of the summer. It’s also much coarser than the highly desirable cool-season turfgrasses, such as Kentucky bluegrass, fine fescue, or turf-type perennial ryegrass, all recommended for our region. They thrive in our climate, especially during the cooler months of spring and fall. Cool-season turfgrass growth slows way down during the heat of summer, but the grasses don’t go brown and dormant if supplied with adequate irrigation.

Bermuda grass doesn’t only infest lawns, it will also invade landscape plantings and gardens. The first reaction of gardeners is to remove it by pulling or hoeing. Remember those rhizomes? If a part of the rhizome is left behind, the grass plant is able to regrow…and it’s unlikely you’ll get all the rhizomes, especially because they can grow quite deep. Fabric mulches aren’t completely effective in controlling a Bermuda grass problem in landscape beds, but are most successful when the sheets are overlapped. Any gaps or holes in the fabric give Bermuda grass a chance to grow. Mulch can be applied over the top of the fabric for a more natural appearance and to preserve the fabric.

There are some herbicides available to help with control, but even these don’t completely eradicate the problem and repeat applications are needed. Combine that with the fact that it can easily reproduce by seed, and you have one very tough weedy grass that seems invincible.

The best herbicide available for control of Bermuda grass is glyphosate, known to many under its original product name of Roundup. It’s now found under different home garden herbicide product names. Glyphosate is taken up by the leaves into the plant and then moved to the roots where it kill the roots. It’s most effective when applied to Bermuda grass when its growing vigorously and is not suffering from drought stress. If in the lawn, don’t mow for two to three weeks before application and then don’t irrigate for several days after application. Often, another application of the glyphosate will be needed.

It’s important to remember that glyphosate is non-selective. It kills any green plant to which it’s applied. That means spot treating the Bermuda grass in lawns and landscapes. If the lawn infestation is severe, killing the entire lawn and starting over again may be the only sensible option. In the landscape, it’s very important to treat only the undesirable grass, keeping the glyphosate off leaves and green stems of plants. The use of a cardboard or plastic shield can help.

There is also another herbicide that you can use for Bermuda grass control in the landscape. It’s called fluazifop, also known as fusilade. It can be found in several home garden grass killer products. Fluazifop is safe to use around many broad-leaf (non-grassy) ornamental plants, but be sure to read and follow label directions as to what plants it’s safe to use around.

Curse you Bermuda grass! There’s no easy way to get rid of you.

Published: 4/7/2007 4:10 PM

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