Nuisance grass in lawn ID help - Ask Extension
Happy Valley, Clackamas County. Trying to ID these grassy weeds in my lawn — I suspect either quackgrass or tall fescue clumps but want to confirm b...
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Nuisance grass in lawn ID help #927923
Asked April 09, 2026, 1:54 PM EDT
Happy Valley, Clackamas County. Trying to ID these grassy weeds in my lawn — I suspect either quackgrass or tall fescue clumps but want to confirm before planning control. Lawn has nearby open field that may contribute to weeds
Clackamas County Oregon
Expert Response
Grass ID gets very detailed and is tough using photos. There’s a chance this isn’t either type of grass, but choosing between the two you name, I’m going with tall fescue because of the reddish-purple base and auricles are not clasped. Here is a page about quackgrass showing photo of clasping auricles. This page from UC IPM describes tall fescue. I can’t find the page anymore that shows the purple base, but this from Michigan State shows the ligule, to help you confirm tall fescue.
Many homeowners spot-spray invading grasses with a non-selective herbicide before re-seeding with their desired turf grass. I don’t know of an herbicide that will kill the fescue but not common lawn grasses. We do have a turf specialist I can consult with if that’s what you’d like to do. He will need closeup photos of the growing points, ligules and auricles to make a firm identification, so send photos if you want to follow-up.
Oh, and as a basic “how-to”, publication EC 1521 covers a lot of information that applies to lawns growing here, and a link at the end of it to EC 1550, which is sort of my everything-lawn-related handbook . The Extension catalog includes articles with other helpful lawn tips.
Many homeowners spot-spray invading grasses with a non-selective herbicide before re-seeding with their desired turf grass. I don’t know of an herbicide that will kill the fescue but not common lawn grasses. We do have a turf specialist I can consult with if that’s what you’d like to do. He will need closeup photos of the growing points, ligules and auricles to make a firm identification, so send photos if you want to follow-up.
Oh, and as a basic “how-to”, publication EC 1521 covers a lot of information that applies to lawns growing here, and a link at the end of it to EC 1550, which is sort of my everything-lawn-related handbook . The Extension catalog includes articles with other helpful lawn tips.
