Quackgrass In My Lawn!
Quackgrass ( Elymus repens) is a cool-season perennial grass. It vigorously spreads by rhizomes. It is a sod-forming grass that can crowd out desirable grasses and weeds. This invasive grass has been shown to be allelopathic. This means it releases chemicals that inhibit the growth of other plants. Large, nearly pure patches are able to form (see picture below). This is due to the invasive nature, extensive rhizome production and spread, and allelopathy of the species. These patches stand out in a lawn due to the ashy, blue-green color of the blade.
How Do I Know If I Have Quackgrass?
The easiest identification feature of quackgrass is its clasping auricles. It can be distinguished from annual ryegrass (Lolium multiflorum) with the presence of rhizomes (i.e. quackgrass has rhizomes and annual ryegrass does not). Quackgrass has rolled vernation and a short, membranous ligule. Lower sheaths are often hairy while upper sheaths are usually smooth. Leaves are an ashy, blue-green color and can sometimes have a longitudinal twist. Typically during the month of June, the grass plant will begin to produce seeds. These seeds are then transferred from the plant by birds or wind to new areas where they are able to begin the germination process and eventually grow into the troublesome weed that homeowners despise.
How Do I Protect My Lawn?
A dense, healthy lawn is the best first defense against quackgrass. Soil disturbance near a quackgrass patch can assist in the propagation and spread resulting from chopped rhizomes. Practices such as tillage can escalate the problem. When reestablishing a turf area with previous issues, laying sod may be a better alternative to seeding because the rhizomes will have a more difficult time thriving. Unfortunately, only nonselective control options exist in cool-season turf. Spot-treating with a nonselective systemic herbicide such as glyphosate will help to manage this grassy weed in cool-season lawns.