Help! Johnson Grass
We are battling serious Johnson Grass. What cover crop would help in a small pasture that is cleared for the moment but still has roots under the soil? Are there any other strategies to combat this invasive weed that is making vegetable and flower gardening very hard? Thanks!
Tags: cover crop, help, invasive weed, johnson grass, pasture
August 19th, 2009 at 1:53 pm
Unfortunately, Johnsongrass is a perennial weed that reproduces from underground stems (it also reproduces by seed, so make sure to never let the grass mature that far), so, as you know, it’s difficult to control! Any cover crop you grow to compete against it should not be tilled in, rather mowed and cut on the surface. If you till into Johnsongrass, new roots and shoots will form from the pieces of underground rhizomes, exacerbating the problem. Alfalfa is a good choice for competition. Here are some other strategies to consider:
“If a johnsongrass infestation does occur, there are several options to choose from in the management of this weed. In certain areas of the state (CA), summer fallowing with a tillage operation every 3 to 4 weeks will give fair to good control by reducing carbohydrate reserves in rhizomes. Dry fallow is not effective in areas with a high water table where moisture in the soil is high enough throughout the summer to allow this weed to grow.” (www.ipm.ucdavis.edu)
This is from the ATTRA website:
http://attra.ncat.org/attra-pub/johnson.html
Solarization is also an option:
http://californiaagriculture.ucanr.org/landingpage.cfm?article=ca.v047n01p19&fulltext=yes
good luck!