Sunday, October 17, 2010

Cheatgrass control should be accomplished this fall. Don't wait!

Downy Brome, Bromus tectorum, known as cheatgrass, is a weedy grass that germinates in the fall, goes dormant in the winter, begins growth again in the spring and will complete growth next summer.
The long sharp awns on the seed penetrate the skin and ears of cats, dogs and other animals. When the plant dries the chances for fire is very likely.

This grass is soft and hairy on the upper and lower side of the leaves. When you pull a leaf down and look at the point where the leaf touches the stem, you will see a membrane (the ligule)  that is very thin and hairy or toothed as seen in the photo below.  The  photo is courtesy of

This weedy grass should be sprayed now if at all possible. Glysphosate is a great herbicide with systemic properties killing roots along with leaves and stems.  However, this herbicide is likely to kill plants you don't want killed if the spray gets on those plants. If you use glyphosate, use it carefully.  Safer chemicals to use include fluazifop-P-butyl and sethoxydim. Fluazifop-P-butyl and sethoxydim are also systemic and will kill roots and rhizomes.

Fluazifop-P-butyl sis old as Ornamec 170 and Ornamec Over-The-Top.  These products can be used in and around ground-covers, shrubs and trees  in landscape beds, container yards and grower nursery fields without damaging broadleaf plants.  Over 500 plants are listed on the label over which this product can be sprayed. Other Fluazifop-P-butyl products registered for use in Colorado in 2010 include Green Light Bermudagrass Killer and Ortho's Grass B Gone Garden Grass Killer.

Sethoxydim is effective on annual and perennial grasses to include turfgrasses.  This material is not effective on sedges. Sethoxydim is sold as Bonide Grass Beater Over-the-Top Grass Killer Concentrate (13% sethoxydim), Ferti-lome Over-the-Top II (18%), Hi-Yield Grass Killer Post-emergence Grass Herbicide (18%), and Poast Herbicide (18%). . Not all of these products are labeled for landscaped areas so read the label.   Treatment of reed canarygrass, a major weed along irrigation ditches significantly reduced seeding and biomass production of this grass, especially when the dead grass was mowed down prior to the next year's application of Sethoxydim.

Products used for burn-down only.  These are not systemic and will not kill the roots.

Scythe is a pelargonic acid and similar fatty acid combination that burns back the top of the plant.  Since cheatgrass is an annual, it has no below ground buds from which to recover.  When used on perennial weeds, you can expect the plant to recover from its below ground buds.  There is no systemic activity with Scythe. This product is not approved for organic production.

BurnOut II is a blend of lemon juice, clove oil and citric acid and provides non-selective control of herbaceous broadleaf and grass weeds. This product is a contact kill and has no root activity. BurnOut II is approved for organic production by OMRI.

Weed-Aside, an ammoniated soap of fatty acids, has no root activity and thus does not kill the roots of perennial weeds. It is quite effective on annual weeds such as cheatgrass.  While this is said to be organic, I can not find any agency that has certified Weed-Aside as approved for organic production.

The smaller the grass is when it is sprayed the more effective the treatment.  Don't wait until next summer to try and control cheatgrass.  Treat and kill it now!

1 comment:

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