Crabgrass is the arch enemy of many a lawn-devoted homeowner.  This weed disturbs the continuity of a perfectly cared-for yard very quickly, and propagates invasively.  It’s undesirable mainly because of its appearance.  Crab grass is a paler green than most choice lawn grasses, which makes it highly visible even when cut short.  It also grows to a greater height more quickly than lawn grasses, and in a peculiar clumping fashion.  These attributes heighten the visibility as well.  During the late summer, when it seeds, it produces very noticeable seed heads, and then turns brown and dies much earlier than lawn grass in the fall.  This leaves large yellow and brown spots in otherwise well tended lawns.

Preventing crabgrass from invading one’s lawn is achieved in part by reducing the areas in which it can easily grow.  The weed can’t grow well in areas with dense, healthy grass, or under thick mulch.  It tends to crop up in marginal areas, such as the edges of flower beds or driveways, where these preventions fail to overlap.

Crabgrass which is already present must nearly always be removed physically—that is, dug up.  This should be done before it goes to seed in the fall.  Once the crabgrass is removed, the area should be treated with a pre-emergent chemical which will hinder the return of the weed.