This is the time of year when people start to notice brown patches in their lawns. As the lawn greens up for the spring, these patches remain brown until sometime in May.
These patches are most likely nimblewill, a perennial grassy weed. Because it’s perennial, once it gets a foothold, it will stick around unless you eliminate it. Eliminating it is not easy, but it can be accomplished.
Nimblewill (Muhlenbergia schreberi) is a warm-season perennial grass. Because it’s a warm season, it doesn’t stay green for a long time in our area. This is why it is the last to green up in the spring and the first to go brown in the fall, making it stick out like a sore thumb in a cool-season lawn.
It is perennial so it sticks around, and it spreads by underground stems or stolons as well as seeds. Spreading underground is one of the challenges in eliminating it.
It loves infertile soil and thin stands of turfgrass. Therefore, in this type of situation, it will take over the lawn.
If you have a few patches of it, get rid of it now and start thickening up the turf. Maintain a regular fertilization schedule (at least twice a year). If you have a lot of nimblewill (more than 50% of the lawn) you may want to consider a do-over.
What you decide to do depends on what I call your lawn philosophy. Do you want a completely green lawn all season, or are you ok with brown patches? This is completely up to you.
I just had a call from a gentleman, and he was redoing some of his lawn where trees were removed. He had a lot of nimblewill and decided to take care of it now.
There are three options in removing nimblewill. The first is to dig it out. When doing this, keep in mind that the stolons are underground and if you don’t get every piece, it will come back.
Therefore, the recommendation is to dig out about 12 inches further than the actual brown patch. If you follow this by thickening up the turf, you may prevent growth from what you missed.
The next is to wait until it is completely green and kill the entire patch with glyphosate (i.e. RoundUp, etc.). This kills roots and you can safely reseed in 10 days.
The final option is a herbicide called Tenacity. I don’t normally recommend this product as it’s geared toward the commercial industry and is sometimes difficult to find.
Tenacity kills just the nimblewill and not the surrounding turf. It is a good product but there are a few challenges for the homeowner.
One is mixing the product according to labeled directions (geared toward industry applications). Tenacity will also cause whitening or bleaching of the grass around it. This isn’t a problem as it will eventually green up after several weeks.
The most important thing in preventing nimblewill again is to keep the lawn thick and healthy with a fertilizer schedule.
Pamela Corle-Bennett is the state master gardener volunteer coordinator and horticulture educator for Ohio State University Extension. Contact her by email at firstname.lastname@example.org.
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