Alternatives to your water-guzzling patch of grass abound
Sunday, 18 July 1999
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By John Begeman, Special to The Arizona Daily Star
THE ARIZONA DAILY STAR
Since water and the lack of it represent a constant concern here, it's time to assess your landscaping in terms of water usage.
If you have a lawn, you probably know from experience how much water is consumed by thirsty grass. But did you know lawns typically use twice the amount of water as the same size area planted in desert landscaping.
Maybe it's time to get rid of your lawn in favor of some low-water-use desert plants. There are many types of attractive, low-water-use ground covers that can be planted in groupings to create drifts of attractive foliage and flowers. They can be used alone or with varieties of native and desert-adapted shrubs.
Summer is best time to kill grass
The best time to remove a Bermuda grass lawn is in the heat of summer. Bermuda is most vigorous in hot weather and is therefore much more susceptible to eradication with chemical herbicides.The herbicide of choice to kill Bermuda grass is glyphosate, most commonly sold under the trade name Roundup. It has systemic properties and as such has the ability to kill grass plants, roots and all. This is very important for eradicating Bermuda grass, which tenaciously comes back from any vegetative parts not killed. Glyphosate is absorbed by the leaf blades and transported down into roots, stolons and rhizomes, killing them and preventing regrowth.
Prior to treating the lawn, make sure it is growing healthy. A week or so prior to spraying the grass with glyposate, fertilize it to stimulate growth. Use an inexpensive, high-nitrogen fertilizer, such as ammonium sulfate (21-0-0). Apply 5 pounds of ammonium sulfate per 1,000 square feet of lawn area and water it in.
Keep watering as you would normally. Allow the grass to grow and do not mow it. The longer the leaf blades, the more efficiently glyphosate will be absorbed. Continue to water the lawn normally until you are ready to apply the glyphosate.
When applying any chemical, follow all label directions. Never apply a chemical pesticide higher or lower than the recommended rate. A lower than recommended rate of glyphosate will not be enough to be absorbed and move into the roots. A higher rate than recommended will have much the same effect. The grass blades will die too soon and the chemical will not be moved down to the roots.
Apply herbicide in morning
The best time to apply the glyphosate is from early morning to midmorning. The spray should be on the grass a minimum of three hours prior to irrigation or rain. Water falling on the grass too soon after application will wash some of the chemical off. Also, be sure to apply the spray to dry leaf blades. If your irrigation comes on at night or in the early morning, wait until the grass blades have dried before applying glyphosate.Put on enough spay to wet the grass blades, but not so much that it runs off. It will also help increase the effectiveness of the spray to add a spreader-sticker to the spray mix prior to application. Spreader-stickers can be purchased at any garden supply store. These products help distribute the spray over the entire leaf and help hold it in place.
After applying the glyphosate spray, be patient! You won't see results overnight. It takes time for the chemical to move into the roots and do its job. You'll have to wait about 10 days before seeing results. In the meantime, water the Bermuda grass as you would normally. Remember, the grass should be healthy and actively growing for the glyphosate to work.
A second or even third follow-up spray may be needed to kill the Bermuda entirely. If after 10 days following application the lawn has yellowed but is not dead, spray it again. Repeat this process until the lawn has turned brown. In the process of spraying the lawn, keep people and pets off until the spray has dried. The chemical nature of glyphosate is such that it breaks down into harmless constituents when it comes in contact with soil, so it is environmentally friendly.
When you're sure the entire Bermuda grass lawn has died, mow the lawn and remove the excess clippings. Add them to a compost pile or use them as a mulch around flowers and vegetable plants in the garden. Spade or till in the remaining dead grass plants and loosen the soil in preparation for the planting of drought-tolerant desert plants.
Wait until fall to plant
It's best to wait until cooler weather this fall to do your replacement planting. And when you plant, consider the use of organic mulches for ground-cover plantings. Some good organic mulches are ground cypress and cedar bark, forest mulch and compost. These have benefits over rock mulch in that they keep the soil cooler, do a better job of holding in soil moisture, and improve the soil by adding humus.Home lawns have a function in providing active play areas for children. But if your kids are grown or if you had a lawn largely for asthetic appeal, consider replacing it with an attractive desert landscape. You'll be saving yourself money and helping your community save one of its most precious resources - water.
John Begeman is the horticulture agent for the University of Arizona's Pima County Cooperative Extension.
