Time to attack that pesky nimblewill

  • Pamela Corle-Bennett
  • Contributing Writer
12:00 a.m. Friday, April 1, 2016 Home Garden

It seems like lawns went from brown to green in no time! However, they don’t look all that great right now.

Early spring when lawns begin to green up they tend to look quite straggly and rough. Turfgrass species aren’t all growing at the same rate in the beginning.

The result of this uneven growth is a lawn with various colors of green and patchiness. Just give it a few mowings, and it will correct itself.

A problem that is showing up very clearly in lawns is a perennial grassy weed called nimblewill.

This perennial is actually considered a weed in most lawns consisting of Kentucky bluegrass, perennial ryegrass and turf type tall fescue lawns.

You’ll notice that all of the desirable species are green right now, and the nimblewill is still brown. I see quite a bit of this as I travel around the Miami Valley.

Nimblewill is a very aggressive perennial weed that encroaches in areas of thinning lawn and can eventually take over a large patch. Enough of these large patches and you end up with a lawn that has more nimblewill than desirable turf.

Since nimblewill is a perennial grassy weed, the only thing that will control it is to kill it with glyphosate, such as Roundup weed killer.

There are a few things to keep in mind before you begin your attack. First of all, glyphosate will kill all green tissue that it comes in contact, including the good turf.

You will have to reseed those areas that you killed out. This can be accomplished in a week or ten days after spray application.

When reseeding, make sure you scratch up the soil surface to get seed to soil contact for best germination and growth.

The most important factor in attacking nimblewill is that you have to wait until it greens up. One of the characteristics is that it greens up later than your other turf species and it turns brown earlier in the fall.

This makes it very apparent in the green lawn right now.

If you spray now while it’s still brown, it won’t absorb the herbicide and consequently won’t kill the weed.

Therefore you have to wait until it greens up completely. This presents a challenge - you won’t spot it as easy in the lawn. Mark the patches now with a flag and you will know where to hit later.

In addition, when you use the herbicide, spray approximately 12 inches outside of the main patch because there are runners and new sprouts hiding in the good grass that you want to be sure and eliminate.

Again, after the appropriate amount of time you can reseed.

Finally, after seeding be sure to follow a regular fertilizer schedule in order to keep the turfgrass thick, preventing weeds from creeping in.

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