Bad grass in Kentucky Blue Grass lawn

Asked June 26, 2019, 1:39 PM EDT

Hello, Would anyone at the extension office be able to take a guess at this grassy weed that is contaminating my kentucky blue grass? Glen Burnie, MD 21061

Anne Arundel County Maryland

3 Responses

It's difficult to distinguish the weedy grasses in your photos. They look freshly mown. Two possibilities are:
nimblewill. This is a perennial grass, somewhat grayish or blueish compared with Kentucky bluegrass. Here's how to manage that: https://extension.umd.edu/hgic/topics/nimblewill
Note that the photo shows both nimblewill (blueish) and Japanese stiltgrass.

The second grass you likely have is Japanese stiltgrass, simply known as stiltgrass. Here's that info: https://extension.umd.edu/hgic/topics/japanese-stiltgrass
This is an annual grass, and its management is completely different. If your weed grass disappears in the winter, it's probably stiltgrass.

Incidentally, a Kentucky bluegrass lawn is high unusual. Kentucky 31 is a variety of tall fescue which is often sold and which is a better grass suited to Maryland weather.. Kentucky bluegrass tends to die out rather quickly from disease and pests.

Ellen

Ellen,

Thank you, the yard is irrigated and contains a mix of Kentucky bluegrass and perennial ryegrass along with other blends of fescue.

Looking at the photo comparisons I think that you are absolutely correct in identifying nimblewill. Thank you for your help. Now I can take steps to control it.

-Adam