Invasion of tall grass or pasture grass.

Asked June 25, 2018, 5:17 PM EDT

For the last few years my sodded lawn has been invaded by a tall clumping grass. I believe it's either tall fescue or orchard grass. I'd like to remove it and replace it with a turf grass because the clumps are too dense. It is now overwhelming the North facing backyard but has only had a small number of plants in the South facing front yard. I've sprayed the clumps with Roundup and have had some success removing them with a thatching rake. I missed an opportunity this spring to spray the germinating clumps while the rest of the grass was still dormant. They stood out clearly as small green clumps on a brown lawn. This makes me think it's orchard grass since it was the first to green this spring. Assuming that I'm able to catch the clumps with Roundup next spring, what would be a good seed to use? Should I try to find seed at a nursery or just use Pennington Sunny or Sun/Shade bags? I've been patching so far this summer with these bags of Pennington on the South and North sides. Also, is there a way to prevent it from returning. There are probably more seeds in the lawn now since it has gotten pretty bad. I'd say 50% of the backyard has the clumps.

Clay County Minnesota

1 Response

Orchard grass is an annual, so I would advise a good pre-emergent herbicide in the spring - this should stop seeds already present in your turn from germinating.

I would recommend a good quality lawn mix (I can't endorse one brand over another), one that does contain an annual in the mix (often turf grass mixes include a small percentage of annual grass) that will fill in any bare spots this season and leave less available for the invading grass/weeds. Maybe consider a weed and feed type product. This will help boost the health of already present perennial grasses while discouraging weed growth.

Another thing to consider is to apply a corn gluten treatment. This works as both a pre-emergent and a fertilizer. Here is an article if you're interested in learning more about it as a lawn care product: