Recognizing common grass weeds in lawns helps you choose the right response instead of treating every grassy-looking patch the same way. This guide covers identification, practical removal, and prevention. Before acting, check your lawn type, the weed’s growth stage, and local product labels: some controls can damage desirable grasses or are restricted in certain areas.
What You’ll Need
- A hand trowel or narrow weeding tool for small patches
- Gloves and a bucket or bag for pulled weeds
- A lawn mower and, if available, a ruler to check mowing height
- Optional: a phone or camera to photograph an unknown weed, plus a lawn-appropriate herbicide whose label lists the weed and your grass type
Step-by-Step
- Inspect the lawn before treating it. Walk the area and note where the plants grow, whether they form clumps or spread, and whether they are annual or persistent. Look closely at the leaf blades, stems, seed heads, and how the plant joins the soil. Photograph the whole plant and a close-up. Identification matters because similar-looking grasses respond differently to control.
- Check for crabgrass. Crabgrass is a warm-season annual that often appears in sunny, thin, compacted, or dry spots. It spreads outward in a low, branching clump, with stems that may root where they touch soil. Its leaves are usually wider and coarser than lawn grass; mature plants can produce finger-like seed heads. Pull young plants before they set seed, loosening the roots with a tool. Bag seed-bearing plants rather than leaving them on the lawn.
- Look for goosegrass and foxtail. Goosegrass commonly forms a flat, pale-centered rosette in compacted areas, with flattened stems close to the ground and seed heads resembling several narrow fingers. Foxtails are annual grasses with soft, bristly, brush-like seed heads; they may grow upright and are easier to spot once heading. Remove small plants before seed heads mature. For widespread annual weeds, prevention and improving the lawn are usually more useful than trying to pull every plant after it has seeded.
- Identify perennial grasses separately. Dallisgrass forms coarse, spreading clumps and tall seed stalks; it can be difficult to distinguish from other clump-forming grasses. Quackgrass has pointed leaves, clasping auricles near the leaf base, and pale underground rhizomes that spread into new shoots. Nutsedge is not a true grass, but is often mistaken for one: its stems are triangular rather than round, and its leaves grow in groups of three. If you are unsure, have a local university extension service or lawn professional confirm the identification before using a selective product.
- Remove isolated plants while they are small. Work when the soil is moist, but not muddy. Insert the tool beside the plant and lift out the crown and as much root system or underground runner as possible. For crabgrass and other annuals, remove the whole plant before it produces seed. For rhizomatous weeds such as quackgrass, avoid chopping runners into fragments; even small pieces may regrow. Bag removed seed heads and dispose of them according to local yard-waste guidance.
- Choose chemical control only after reading the label. A selective post-emergent herbicide may control a named weed in a specific lawn species, but one product does not safely treat every grass weed or every turf type. Confirm the target weed and acceptable lawn grasses on the label, then follow its rate, timing, weather restrictions, protective equipment, and re-entry instructions exactly. Do not apply more than directed, mix products unless the label allows it, or spray in wind. Keep people and pets away for the labeled period. Avoid treating drought-stressed, newly seeded, or heat-stressed turf unless the label specifically permits it.
- Prevent new annual weeds. Crabgrass pre-emergent products can reduce germination when applied at the timing and rate on the label, often around local soil-warming cues rather than a fixed calendar date. They do not kill established plants, and many interfere with grass-seed germination. Check whether overseeding is compatible and observe the label’s interval before seeding. Pre-emergents generally do not control established perennial weeds.
- Help desirable turf fill the gaps. Mow at the recommended height for your lawn species, using sharp blades and avoiding scalping. Water deeply when needed rather than lightly every day, and correct drainage or compaction where practical. Fertilize only according to a soil test or local lawn guidance. Repair bare patches with a suitable grass seed at the recommended season; a dense lawn leaves less room for many weed seedlings.
- Recheck and record results. Inspect treated patches after the label’s stated interval, not immediately. Some weeds need a second treatment, but repeat only if the label allows it and the lawn remains within the specified conditions. Note which weeds return and where; repeated growth in the same spot may point to compacted soil, poor drainage, shade, or a persistent underground root system.
Common Mistakes
- Guessing the weed: Treating nutsedge, crabgrass, and perennial grasses as interchangeable can waste effort or injure turf. Confirm the plant first.
- Pulling only the visible leaves: Leaving crowns, roots, or rhizomes behind allows some weeds to regrow. Lift carefully and follow underground runners where possible.
- Waiting until seed heads spread: Mature annual weeds can distribute seed across the lawn. Remove them early and handle seed-bearing plants carefully.
- Scalping the lawn to suppress weeds: Cutting too short weakens turf and exposes soil, often making future invasion easier. Follow the recommended mowing height for your grass.
- Overapplying herbicide: More product does not mean better control. It can damage the lawn, create runoff, or violate the label. The label is the legal and safety guide.
Tips
- Keep a photo record of unfamiliar weeds, including a seed head and the plant’s base; these details can help with identification.
- Use a hand fork on small clumps soon after rain or irrigation, when roots release more readily.
- Clean soil and seed from mower blades, shoes, and tools before moving from an infested area to a clean one.
- Address the conditions that favor weeds. Compaction, bare soil, irregular watering, and mowing too short commonly give weeds an advantage.
- For a large infestation or a lawn containing mixed grass species, get local advice before using a lawn herbicide.
Troubleshooting
The weed returns after pulling: You may have left a crown or underground runner. Dig out a small area carefully, removing as much root material as practical, and monitor it. Persistent weeds may need repeated, correctly timed control.
A herbicide did not work: Check that the weed was correctly identified, the product lists it, and application conditions and timing matched the label. Established or stressed weeds may be harder to control. Do not immediately apply extra product; wait the interval specified on the label and seek local advice if needed.
The lawn is damaged after treatment: Stop further applications. Follow the label’s instructions for exposure or turf injury, and contact the product manufacturer, a local extension service, or a qualified lawn professional with the product name and application details. Do not reseed until the label’s waiting period has passed.
Weeds keep appearing in bare patches: Restore healthy turf rather than repeatedly treating open soil. Correct the underlying problem, then reseed or patch at the right season for your lawn species. Check that any pre-emergent treatment will not prevent the seed from germinating.
Frequently Asked Questions
How can I tell crabgrass from ordinary lawn grass?
Crabgrass usually grows as a low, spreading clump with branching stems and coarser leaves. Seed heads often resemble several fingers. Check the plant’s growth habit as well as its leaves.
Can I pull crabgrass by hand?
Yes. Small plants are easiest to remove when the soil is moist. Pull out the crown before seed heads mature, and dispose of seed-bearing plants so they do not spread seed.
Will a pre-emergent herbicide kill weeds already growing?
Usually not. Pre-emergents are intended to prevent seeds from germinating; they do not remove established weeds. Follow the product label, especially if you plan to seed the lawn.
Why does quackgrass keep coming back?
It spreads through underground rhizomes, and fragments left behind can produce new shoots. Carefully remove as much of the runner system as possible, or seek advice on a control labeled for your lawn type.
Is nutsedge a grass weed?
No. It is a sedge, though it can look grass-like. Its triangular stem and leaves arranged in groups of three are useful clues; control depends on correct identification and a product labeled for the lawn and weed.
When should I call a professional?
Get local expert help when you cannot identify the weed, it covers a large area, the lawn contains several turf species, or previous treatment has injured the grass. A local extension service can often help identify weeds from clear photos.