Crabgrass Control

Death and taxes are inevitable, or so goes the saying. So it seems, is crabgrass. Crabgrass is often considered the scourge of home lawns. With the possible exception of dandelions, no other weed creates as many headaches, or, is responsible for a large portion of the lawn care product market. Unfortunately, it's one of the most difficult weeds to control once it has sprouted.

Crabgrass is a weed because of its size and appearance. Leaf blades tend to be three to four times wider than bluegrass, giving the plant a coarse appearance. Homeowners could probably live with the coarse appearance if the plant grew like bluegrass. However, it doesn't. Crabgrass tends to be an open or prostrate plant that shades and smothers the nearby turf plants.

The most common crabgrass is the hairy crabgrass. Leaves are fuzzy and stems are rolled. The seed head has three to nine branched "fingers," giving the plant a bird's foot appearance. Each finger can produce a hundred seeds. Unlike most of the desirable turfgrasses, crabgrass will flower below the mower blade.

Crabgrass starts germinating when soil temperatures are 50 to 55 degrees F for ten or more days. Germination can take place over 6 weeks. Proper lawn maintenance practices limit crabgrass invasions. A dense stand of turfgrass prevents the weed from germinating and establishing. Fall fertilizing, overseeding, aeration and thatch control can limit spring problems.

Pre-emergence herbicides provide excellent weed control for crabgrass. The compound doesn't prevent the weed seed from germinating, but kills the newly sprouted seedling. Late April to early May is an ideal time to apply pre-emergence control.

The majority of pre-emergence weed control compounds will provide protection for four to six weeks. A follow-up application four to six weeks after the first application helps control many warm season grasses such as goosegrass, foxtail and barnyard grass.

It is difficult to sow grass seed in the spring and control crabgrass. Weedkillers aren't able to distinguish between different types of grasses. Germinating bluegrass or fescue seeds will be killed along with the crabgrass seedlings. The compound Siduron or Tupersan can be used to control crabgrass and allow some grass seeding. However, the chemical must be used at half the rate listed on the package to prevent damage to grass seed.

Make sure to read and follow all label directions when applying pesticides.

Source: David Robson, Extension Educator, Horticulture, Springfield Extension Center

 

Spring 1998
University of Illinois Booksale | Zoysiagrass! Can You Believe the Ads? | Crabgrass Control | Choosing Home Lawn Care Services | Selecting a Tree Service or Arborist | All America Selections 1998 | All Tomato Varieties Certainly Not the Same | Some Noteworthy Perennial Combinations | Bug Bites | Lawn Care Calendar | Cybergarden Sites | Hort Shorts | Hort Tips | Healthy Eating: Butter vs. Margarine | Health Update: Vitamin & Mineral Supplements | Food Safety: Eggs | Health & Household Update | Did You Know?

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