One of the pitfalls that can derail a beautiful lawn is the appearance of coarse, off-color, and/or ragged clumps of grass that look different than the more slender blades of grass that were planted. These are grassy weeds that have elbowed their way into small openings in the lawn. They’re especially common in new lawns in which the planted grass hasn’t had time to fully colonize the loosened soil and choke out the competition.

Unwanted grass seed can sneak in on trucked-in soil or the backs of birds, they can blow in from nearby fields or weedy neighboring lots, and they can even be in bags of inferior grass-seed mixes.

The key to controlling grassy weeds depends on whether they’re annual grasses (ones that live one growing season, produce seeds, then die off) or perennial grasses (ones that come back year after year).

Get a jump on annual grassy weeds

Annual grassy weeds are easier to control because they die off at season’s end and depend on sprouting anew from fallen seeds the following spring. That’s when lawn-owners can shut the door by applying a weed preventer each year, such as the granular GreenView Fairway Formula Spring Fertilizer with Crabgrass Preventer.

When applied as directed, GreenView Fairway Formula Spring Fertilizer Weed & Feed and Crabgrass Preventer will control the following annual grassy weeds:

  • Annual Bluegrass (Poa annua)
  • Annual Ryegrass
  • Barnyardgrass
  • Crabgrass
  • Crowfootgrass
  • Foxtail (green and yellow)
  • Goosegrass
  • Kikuyugrass (seedling)
  • Perennial Ryegrass
  • Smutgrass (seedling)
Perennial grassy weeds
Perennial grassy weeds can be tough to eradicate, but by overseeding in the spring & fall, you can start to push the weeds out and make room for good grass.
Photo by George Weigel

What about perennial grassy weeds?

Perennial grassy weeds include wide-bladed clumping grasses such as quack grass, poor-quality varieties of tall fescue, and orchard grass, as well the more narrow-bladed nimblewill and nutsedge. These are tougher opponents because they come back from their own roots each year, rendering weed preventers useless.

If you have patches in the lawn of perennial weeds, consider doing a spot treatment with an herbicide that will kill perennial weeds. Check product labels to ensure it will kill the weed you’re looking to remove.

In the long run, the best defense against grassy weeds – and any weed, for that matter – is a good offense. Overseed your new lawn each fall for a few years to speed up a thick lawn and use good cultural practices, such as fertilizing, cutting high, and irrigating until the lawn is well established.