The return of summer means sunny days, balmy nights, and crabgrass. What? What is crabgrass? Crabgrass is a light green, grass-like weed that appears in summer, rapidly forming low-growing mats in lawns or in cracks in the sidewalk or driveway. Wide, coarse leaf blades grow out from the center in a star-shaped pattern that makes the rounded mats look a bit like a bunch of crab legs, hence the name.
Crabgrass gets confused with other grassy weeds, like unwanted Fescue. So, what does crabgrass look like, and how can we differentiate it from other weeds? Rather than growing upright, like typical grass blades, crabgrass leaves grow low to the ground, nearly horizontal and radiating out from the center of the mat it forms. The stems have a reddish-purple cast at the center of the mats. Crabgrass is a fast-growing annual that crops up in bare or sparse patches in a lawn, where it quickly out-competes the turfgrass for nutrients, water, and root space. Early detection and prompt action are critical when combatting crabgrass.
Identifying Crabgrass in Your Lawn
Identifying crabgrass is the first step to controlling it. So, it’s important to recognize how its appearance changes throughout the season:
New Crabgrass
Young crabgrass sprouts have light green, tender, fine-textured leaves that are soft to the touch. The blades are smooth, linear, fairly short, and form tight clusters close to the ground.
Mature Crabgrass
As crabgrass matures over the season, the leaves grow longer, wider, and flatter. They become more coarse, developing a darker green hue and fine hairs running along the edge of the leaves. The blades thicken and feel tougher while the mats enlarge. Their aggressive growth makes the lawn appear patchy.
Seed Heads
Crabgrass produces seed heads in late summer to early fall. They emerge on upright stems with thin, thread-like spikes resembling miniature wheat heads. The seed heads emerge silvery green, then mature to a purplish-brown. A single plant can produce up to 150,000 tiny seeds!
Why Crabgrass is a Problem
Crabgrass is an enduring problem throughout most of the United States for several reasons:
- Aggressive Growth: Crabgrass is an aggressive weed that spreads quickly throughout your lawn. It competes fiercely with turfgrass for space, light, water, and nutrients and can take over weaker areas of the lawn.
- Appearance: The grass-like look of crabgrass is difficult to discern in the lawn when it is young. It’s not until it matures and crowds out the turfgrass that it makes the lawn look uneven and patchy.
- Lifecycle and Reseeding: Although crabgrass is an annual plant that dies off after growing for a single season, it leaves behind thousands of seeds that will sprout the following spring.
- Adaptable: Crabgrass is highly adaptable and able to thrive in drought and other challenging conditions. It can quickly out-compete more tender turfgrasses.
- Difficult to Control: Well-established crabgrass is very hard to control. Mowing the lawn once the seeds are set simply spreads the weeds throughout the lawn. It often requires targeted and well-timed herbicide and manual removal that gets the entire root system.
How to Get Rid of Crabgrass
The best time to get rid of crabgrass is in the early spring before the leaves even sprout. Apply a targeted pre-emergent herbicide to the lawn, following the manufacturer’s directions. Once you see crabgrass in the lawn, a pre-emergent will have no effect. Now, it’s time to apply a targeted post-emergent herbicide. Always choose one that will be safe for your turfgrass type, and follow the manufacturer’s instructions.
Manual weeding is another method for controlling crabgrass. Use a weeding fork or trowel so you can dig up the root system. However, once the seed heads develop, weeding will spread the seeds throughout the lawn, so cut them with scissors and collect the stems for careful disposal.
Best Crabgrass Killers for Lawns
Choosing the right crabgrass killer is tricky because it can also affect your turfgrass. Once the soil temperature reaches 55°F, apply targeted pre-emergent herbicides to prevent crabgrass seeds from germinating. Pre-emergent herbicides with the active ingredient Prodiamine or Dithiopyr are safe to apply to well-established lawns, though they will inhibit the germination of your turfgrass seed. Once you see crabgrass mats in the lawn, post-emergent herbicides containing Fenoxaprop-P-ethyl are effective, targeting the weeds without damaging your lawn.
Some people prefer a more natural crabgrass killer like white or apple cider vinegar, but it is only effective against very young plants. For best success, spray the crabgrass on a sunny day within two weeks of germination. Take care not to spray the turfgrass, because the vinegar will burn it.
Lawn Pride’s Services for Crabgrass Control
For over 40 years, Lawn Pride® has provided homeowners with comprehensive lawn care services so they could enjoy lush, healthy lawns without the guesswork (and backaches). We stand behind our work with the Neighborly Done Right Promise™, so you are certain to be pleased with our service. We’re happy to take over your crabgrass control efforts so you can relax and enjoy a beautiful lawn.
We’re always happy to discuss lawn care, so contact us with any questions. When you’re ready for us to make your lawn the pride of the neighborhood, just request a free estimate, and we’ll get started!
This article is intended for general guidance only and may not apply to every situation. You are responsible for determining the proper course of action for your property and your situation. Lawn Pride is not responsible for any damages that occur as a result of any advice or guidance derived from blog content. For the most accurate guidance, contact an independently owned and operated Lawn Pride for more information and a professional on-site assessment.