This week’s Weed – Cheatgrass
ChiloquinNews article July 30th, 2012
Cheatgrass or drooping brome (Bromus tectorum), is a grass native to Europe, southwestern Asia and northern Africa. It has been introduced to southern Russia, west central Asia, North America, Japan, South Africa, Australia, New Zealand, Iceland, and Greenland. It was first found in the United States in 1861 and is now found throughout the US except in a few southern states. It is most abundant in the Great Basin, Columbia Basin and California. In my 5 years in the Chiloquin area I have seen the cheatgrass population explode here.
Cheatgrass is notorious for its ability to thrive in disturbed areas, but it also will invade undisturbed areas. As with most non-native species, it has no biological predators in North America, giving it an advantage over native species in competition for nutrients, sunlight, and water. It has an extensive root system and the capability to reduce soil moisture to the permanent wilting point to a depth of 2 ft, further reducing competition from other species. The seeds are dispersed by wind, and by sticking to fur or socks. They are a danger to pets because they have one-way microscopic barbs that allow the seed to work its way into fur, skin, and mucous membranes, but not work back out. Sometimes the seeds must be surgically removed.
It is an annual bunchgrass, usually germinating in the autumn, overwintering as a seedling, then flowering in the spring or early summer. Growing so early in spring provides it with a competitive advantage by allowing it to grow tall before native species emerge. During years of high rainfall, it can produce more than 10,000 plants per square yard. It turns brown and dies by early summer leaving behind thick, dry grass and creating extreme wildfire hazards.
In areas where cheatgrass is well established the intervals between fires is decreased, and native plant communities inextricably altered. A typical cheatgrass fire on flat terrain with wind speeds of 20 miles per hour may generate flames up to eight feet high and the fire can travel more than four miles per hour. Grass fires are dangerous because they move quickly and act as ladder fuels, igniting larger and more volatile vegetation. Due to its highly flammable nature, it is critical for those who live, play or work in “cheatgrass country” to know not only how to identify and eradicate it, but also take precautions not to ignite it!
The key to eradicating cheatgrass is diligence — you must be persistent and continue follow up treatments for up to five years (or however long it might take) because cheatgrass seed may survive in soil that long, and they will always be blowing in from roadsides and neighboring properties. If you have the dedication of a saint, you can hand pull during spring and fall and repeat when new plants appear, and do it all before the grass flowers and sets seed. Mowing is not recommended for long-term control as mown plants can still produce seed. Intensive sheep browsing of cheatgrass in early spring has been used to reduce fire danger in the hills adjacent to Carson City, NV. Roundup will kill it, but also will kill everything around it, so that’s not a good control method either. This spring (in March – really winter still) I tried a grass specific herbicide with great success. Cheatgrass had been steadily encroaching in every nook and cranny, and I think I knocked it back about 80%. Another treatment next spring and then I will only have to cope with the new seeds that blow in every summer. These grass-killing herbicides are only effective if used on small seedlings, so for cheatgrass, it’s March, or not at all.