JoAnne Skelly: Cheatgrass: What to do about it

My friend Jose asked me if he sprayed cheatgrass would it sterilize the seeds. He hoped if he applied an herbicide before weed-eating, it would kill the seeds, which were going to be spread all over as he cut.

The answer, unfortunately, is “no.”

This noxious weed is one of the most common plants in Nevada. It germinates in the early or late winter months. Cheatgrass grows in spring and dies by early summer.

In a wet year, this grass can exceed 10,000 plants per square yard. It can be several inches to more than 18 inches tall. It has a nodding seed head that resembles a shepherd’s crook. There’s often a tinge of red or purple in the leaves. The seeds are notorious for getting stuck in socks and dogs’ ears.

Cheatgrass is probably the most easily ignitable vegetation on our properties and Nevada’s rangelands. If started on a windy day, a cheatgrass fire can produce flames more than 8 feet tall and travel 4 1/2 miles per hour. Dry cheatgrass also serves as the kindling necessary to ignite hotter-burning plants such as juniper, sagebrush and pine, creating more intense wildfires. Cheatgrass is abundant this spring.

To be more fire-prepared, remove cheatgrass growing within at least 30 feet of your home and other buildings, preferably before it dries out. Use a lawnmower with a mulching blade or cut it with a weed eater, but then rake up and remove as many seeds as possible. It’s easy to pull these shallow-rooted plants by hand. Preemergent herbicides containing the active ingredients trisulfuron or trifluralin can be applied in the early fall before the plants reappear.

For information about using preemergent herbicides for weed control in home landscapes, read my publication at http://www.unce.unr.edu/publications/files/ho/2011/fs1167.pdf.

Apply post-emergent herbicides containing glyphosate, sethoxydim or fluazifop-p-butyl while the plant is green and growing, but before the seed heads develop. It’s too late at this point for herbicide applications.

The steps to long-term control are to kill existing plants; prevent new cheatgrass plants from producing seeds; prevent seed germination and seedling growth of seeds already in the soil; and reseed cheatgrass control areas with desirable vegetation.

If you’re working or playing in cheatgrass country, be extremely careful. Always have water and a shovel nearby. Do not park your vehicle over dry cheatgrass. Properly dispose of cigarettes and matches. Instruct your children not to play with matches or fireworks. Have a cell phone available to report fires.

JoAnne Skelly is Associate Professor & Extension Educator, Emerita at University of Nevada Cooperative Extension. She can be reached at skellyj@unce.unr.edu.