Which Grassy Weed is in My Lawn?

It is not uncommon for a customer to believe they have crabgrass in their lawn, when in fact, they may have one of several perennial uncontrollable grassy weeds growing in their lawn.  The difficulty is telling which grassy weed is present.  Without getting into a lot of detail, here are a few simple clues to tell which grassy weed may be growing in your lawn.

  • Crabgrass:  This annual grassy weed grows flat to the ground and it looks like it has been stepped on.  Its growth habit resembles the spokes of a wheel.  The leaf blades are light green in color.  The center of the plant may be tinged with purple, but not always so.  As the seed head develops, its shape resembles a bird’s foot.  It is usually found along driveways, sidewalks, and street edges. Since there are two species of crabgrass that grows in the Midwest – Large and Hairy, there may be hairs growing on the plants as well.
  • Coarse Fescue:  This perennial grassy weed is often called crabgrass as it seems to grow better in the summer and can be more noticeable during summer heat and drought conditions.  It will grow in isolated patches throughout a lawn or in areas that are drier.  Identifying characteristics of this plant include a clump-growth habit, prominent veins on the leaf blade and the leaf edge or margin is serrated.  If you run your finger down along the edge, it will feel sharp, like a serrated knife. 
    Improved varieties of this turfgrass have been cultivated due to its ability to withstand more heat and drought than traditional cool-season grasses like Kentucky bluegrass and perennial ryegrass.  The improved cultivars often referred to as turf-type tall fescue, can be found in many seed mixes that are sold throughout the Midwest. 
  • Quackgrass:  This is another common perennial grassy weed that usually grows in large patches.  The leaf blades are a lighter color than of other cool-season grasses and the blades are sharply pointed at the tip.  In order to properly identify this grass, you need to pull up a plant so that you can see the sheath (stem) and where the leaf blade meets the stem.  If you look closely where the leaf blade meets the sheath, you will see two little growths that resemble little fingers wrapping around the sheath.  These are called auricles and they are the main identifying characteristic of quackgrass.
    One other identifying characteristic of quackgrass is its root system of aggressively growing rhizomes that can grow for many feet underground before surfacing.  Even if you were successful removing much of the root system, even a small section left behind can develop into a new grassy weed.

There are control measures for these weeds, but coarse fescue and quackgrass require the use of non-selective weed control products that contain glyphosate and then reseeding the area once the plants have died.  This is best done in late summer and early fall. 

Crabgrass begins to die when temperatures start to cool, and the amount of sunlight reduces in the late summer and early fall. There are weed control products that can be applied to crabgrass before it gets too old.  The best way to prevent crabgrass in the future is to apply a crabgrass preventer in the spring and, above all else, mow at a height of 3 inches all season long. 

If you think you may have a problem with these grassy weeds, contact Spring-Green so that we can provide proper recommendations to help your lawn improve.