Working together to strengthen and support noxious weed management efforts in Montana.

Priority 3 Weed

Weed of the Week – Cheatgrass

Thursday, September 9th, 2010


Cheatgrass is a regulated plant and not a Montana listed noxious weed.

Introduction Cheatgrass is known by a variety of names including:  downy brome, downy cheat, and downy bromegrass.  Whatever name you know it by you probably know it is one of the most problematic weeds in Montana.  Being a winter annual has given it some advantages over other plants.  Winter annuals germinate in the fall and continue to rapidly grow until temperatures are no longer conducive of growth.  It is possible under certain conditions that growth will continue throughout the winter, especially in the root system.  Germination may occur in the spring as well, depending on conditions.  Whether or not it continues to grow throughout the winter, fall germination gives cheatgrass a considerable advantage over most of our natives.  In addition to this advantage, cheatgrass has an incredibly rapid growth rate.  Five weeks after germination cheatgrass has twice the biomass of desirable grasses that have had the same length of time to grow.

Cheatgrass originated in Asia and was accidentally introduced to North American multiple times in several independent events.  Some of the first introductions are thought to be from ship ballast and railroad packing materials.  The first report of cheatgrass in North America came from British Columbia in 1890.  Cheatgrass was first reported in Montana in 1898 in Missoula County and by 1980 every county in the state had it.

Concerns Depletion of soil water is one of the main processes by which cheatgrass competes with perennial vegetation.  It is able to deplete soil water before it is available to other vegetation because of its fall germination and rapid growth.  The roots of cheatgrass can be much deeper in the soil tapping into the water table and depleting it before other roots have had the opportunity to reach those depths.  It is possible that cheatgrass will diminish the underground water reserves and produce seed for the next generation before the hot, dry part of our summers, leaving no water for other plants that are trying to survive and produce seed.

Cheatgrass has a dramatic effect on the fire regimes on grasslands.  Cheatgrass has the tendency to fill in the spaces between bunchgrasses, which increases the fuel for fire and promotes larger and more frequent fires.  The shortened interval and increases intensity of fires, due to cheatgrass, makes it difficult for perennial vegetation to recover before the next fire.  This leads to an increased population of cheatgrass, which in turn leads to more frequent and intense fires.  Eventually the perennial vegetation will be removed from the system and a monoculture of cheatgrass will remain.

Identification Cheatgrass plants can be anywhere from 6-24 inches tall depending on the resources available.  At emergence the leaves are browish-green.  They turn reddish-purple at maturity.  The leaf blades, which are covered in soft hairs, are around 1/32 inch wide and 2-6 inches long.  The seed-head droops to one side of the stem and has numerous 3/8-5/8 inch long awns (needle-like extension from the seeds).

What can you do? Prevention is the key!  If it is too late to prevent cheatgrass from establishing on your property, which it is for most of us, then there are a few other options.  The goal behind controlling and ultimately eradicating cheatgrass is to stop seed production.  Cheatgrass is an annual, meaning that every plant dies at the end of the growing season.  The only way for cheatgrass to persist in an area is for it to produce seeds every year.  These seeds are only viable for up to 3 years.  This means that if you can stop your cheatgrass from producing seeds for 3 years, you will have a greatly reduced the population.  Some ways to stop seed production are:  mechanically (hand-pulling, mowing, weed-whacking), chemically (using herbicides – call the weed district for more information), grazing (it is good forage in the early spring for cattle, sheep, and goats), and revegetation (competition is imperative in reducing cheatgrass populations).  The integration of all of these tools is more effective than any of the tools alone.  Timing is also very important—mechanical control, chemical control, and grazing all must be done before the plant turns purplish-red (once it is purple seed production is too far along and the seeds will still be viable).  If you have any questions about cheatgrass or any other weed please call the weed district.

Visit the MWCA Weed ID pages for additional information and pictures of cheatgrass.

This series of articles was developed by Ravalli County.  If you would like to use these articles please contact Ravalli County Weed District Weed Coordinator at (406) 777-5842.

Are noxious weeds ranked or prioritized?

Monday, May 17th, 2010


In 2010 the Montana Department of Agriculture revamped the noxious weed priority system.   Noxious weeds are now rank one of 5 priorities.

Priority 1A – These weeds are not present in Montana.  Management criteria will require eradication of detected; education and prevention.

Priority 1B – These weeds are have limited presence in Montana.  Management criteria will require eradication or containment and education.

Priority 2A – These weeds are common in isolated areas of Montana.   Management criteria will required eradication or containment where less abundant.  Management shall be prioritized by local weed districts.

Priority 2B – These weeds are abundant in Montana and widespread in many counties.   Management criteria will require eradication or containment where less abundant.  Management shall be prioritized by local weed districts.

Priority 3 – Regulated Plants – NOT Montana Listed Noxious Weeds.  These regulated plants have the potential to have significant negative impacts.  These plants may not be intentionally spread or sold other than as a contaminant in agricultural products.  the state recommends research, education and prevention to minimize the spread of the regulated plant.

Download a copy of the current priority list of Montana Noxious Weeds.

MSU Montguide: Cheatgrass: Identification, Biology and Integrated Management

Friday, November 20th, 2009


Montana State University provides a great collection of extension publications.  Many of these are available online, and provide a great way to learn more about some of the noxious weeds in Montana.

Cheatgrass is being added to our Priority 3 List.  Learn all about this invader in in a Montguide devoted to cheatgrass.

This Montguide describes cheatgrass biological and ecological characteristics. It also provides mechanical, cultural and chemical management options to control this species in crop and non-crop situations.