Weeds are your lawn’s way of telling you something. Every weed species thrives in specific conditions — compacted soil, low nitrogen, shade, overwatering. Identifying what’s growing tells you not just what to spray, but what’s wrong with your lawn.
This guide covers the 10 most common lawn weeds in the US, how to identify each one, why it appeared, and the most effective control methods.
Grassy Weeds
1. Crabgrass (Digitaria)
Identification:
- Light green, spreading grass that forms low, star-shaped clumps
- Leaf blades are wider than your lawn grass
- Grows flat (prostrate) along the ground
- Appears in late spring / early summer when soil temperatures exceed 55°F
Why it’s there: Thin turf with bare spots. Crabgrass is an opportunist — it fills gaps that healthy turf should occupy. Compacted soil and overwatering create perfect conditions.
Control:
- Prevention: Pre-emergent herbicide when soil temperature reaches 50-55°F
- Post-emergent: Quinclorac (Drive XLR8) is the gold standard for crabgrass in established lawns. Apply when plants are young (1-3 tillers).
- Cultural: Maintain thick turf at proper mowing height to shade out germinating seeds.
2. Goosegrass (Eleusine indica)
Identification:
- Dark green, flat-growing grass resembling a zipper or wagon wheel
- Very flat against the ground — even flatter than crabgrass
- Silvery-white base where stems meet
- Appears later than crabgrass, when soil temps exceed 60°F
Why it’s there: Compacted soil, especially in high-traffic areas. Goosegrass loves compacted, heavy clay soils where other grasses struggle.
Control:
- Prevention: Pre-emergent (same as crabgrass, but apply the second split application at 60°F soil temp)
- Post-emergent: Quinclorac is less effective on goosegrass. Use fluazifop (Fusilade) or hand-pull individual plants.
- Cultural: Core aeration to relieve compaction.
3. Nutsedge (Cyperus)
Identification:
- Bright, lime-green blades that grow faster than your turf and stick up above the lawn
- Leaves are V-shaped (triangular stem — “sedges have edges”)
- Not a grass — it’s a sedge, which is why grass herbicides don’t work on it
- Two types: yellow nutsedge (most common) and purple nutsedge
Why it’s there: Excess moisture. Nutsedge thrives in areas that stay wet — poor drainage, over-irrigation, or low spots that collect water.
Control:
- Prevention: Improve drainage. Fix low spots. Reduce irrigation frequency.
- Post-emergent: SedgeHammer (halosulfuron) or Certainty (sulfosulfuron). These are sedge-specific herbicides — general broadleaf or grass herbicides won’t work.
- Cultural: Pull individual plants, but get the tuber (underground nut). If you just pull the top, it grows back.
Broadleaf Weeds
4. Dandelion (Taraxacum officinale)
Identification:
- Everyone knows this one: bright yellow flowers, fluffy seed heads, deeply lobed leaves forming a rosette
- Deep taproot (can be 6-10 inches long)
- Leaves are “tooth-shaped” (the name comes from French dent de lion — lion’s tooth)
Why it’s there: Thin turf, low fertility, and compacted soil. Dandelions establish where grass is weak. They’re also prolific seeders — a single plant can produce 15,000+ seeds.
Control:
- Post-emergent: 2,4-D or triclopyr. Apply when dandelions are actively growing (spring or fall). Products like Weed B Gon or Trimec work well.
- Manual removal: Dig out the entire taproot with a dandelion tool. If you break the root, it regrows.
- Cultural: Thick, healthy turf at the proper mowing height crowds out seedlings.
5. White Clover (Trifolium repens)
Identification:
- Three-part leaves (trifoliate) with a white chevron marking on each leaf
- Low-growing, creeping habit with white flower heads
- Stays green even in drought and poor soil
Why it’s there: Low nitrogen. Clover is a legume — it fixes its own nitrogen from the air. It shows up when your soil nitrogen is depleted, essentially doing for free what fertilizer should be doing.
Control:
- Post-emergent: Triclopyr or a three-way herbicide (2,4-D + dicamba + MCPP). Most broadleaf herbicides handle clover, but triclopyr is the most effective.
- Cultural: Increase nitrogen fertilization. When nitrogen levels are adequate, grass outcompetes clover naturally.
- Alternative view: Many homeowners now want clover in their lawns for its drought tolerance, pollinator benefits, and nitrogen fixation. If you’re not spraying herbicides, clover is arguably beneficial.
6. Henbit (Lamium amplexicaule)
Identification:
- Square stems (it’s in the mint family)
- Purple tubular flowers in spring
- Scalloped, rounded leaves that clasp the stem
- Winter annual — germinates in fall, flowers in spring, dies in summer
Why it’s there: Thin turf in fall allows germination. Common in lawns that are stressed or thin going into winter.
Control:
- Prevention: Maintain thick turf through fall. Fall pre-emergent at soil temp 70°F and dropping prevents germination.
- Post-emergent: 2,4-D or triclopyr in early spring before flowering. Once it flowers, it’s already produced seeds for next year.
7. Spurge (Euphorbia)
Identification:
- Low, mat-forming weed with small oval leaves
- Leaves often have a dark reddish-purple spot in the center
- Broken stems ooze milky white sap (distinctive)
- Summer annual — appears in late spring when soil temps exceed 60°F
Why it’s there: Hot, dry conditions with thin turf. Spurge thrives in compacted, dry soil that stresses grass.
Control:
- Prevention: Pre-emergent (same window as crabgrass)
- Post-emergent: 2,4-D + dicamba, or products with quinclorac. Spot spray — don’t broadcast for a few spurge plants.
- Cultural: Maintain adequate irrigation and thick turf. Address compaction.
8. Chickweed (Stellaria media)
Identification:
- Small, bright green, opposite leaves on trailing stems
- Tiny white star-shaped flowers
- Cool-season weed — most active in fall, winter, and early spring
- Thrives in moist, shady areas
Why it’s there: Excess moisture, shade, and thin turf. Common in overwatered lawns or areas with poor air circulation.
Control:
- Post-emergent: Triclopyr or 2,4-D in fall or early spring while actively growing
- Cultural: Improve drainage, reduce watering, address shade with shade-tolerant grass varieties
Weed Identification Tips
Look at the Growth Habit
- Flat/prostrate: Crabgrass, goosegrass, spurge
- Upright/rosette: Dandelion, plantain
- Trailing/creeping: Clover, chickweed, creeping Charlie
Check the Leaf Shape
- Grass-like blades: Crabgrass, nutsedge, goosegrass (but nutsedge has triangular stems)
- Round/oval: Clover, chickweed, spurge
- Lobed/jagged: Dandelion, henbit
Note When It Appeared
- Spring/early summer: Summer annuals (crabgrass, spurge, goosegrass)
- Fall/winter: Winter annuals (henbit, chickweed, Poa annua)
- Year-round: Perennials (dandelion, clover, nutsedge)
Use AI Scanning
Modern apps like Lawn Command include AI-powered scanning (TurfCheck) that can identify weeds from a photo. Point your phone camera at the weed, and the AI identifies the species with treatment recommendations. This is especially useful for weeds that look similar — like crabgrass vs. quackgrass vs. tall fescue clumps.
The “Why Did This Weed Show Up?” Framework
Every weed tells a story:
| Weed | What It’s Telling You |
|---|---|
| Crabgrass | ”You have thin spots and your turf is stressed” |
| Clover | ”Your nitrogen is low” |
| Nutsedge | ”This area stays too wet” |
| Dandelion | ”Your soil is compacted and your turf is thin” |
| Goosegrass | ”Your soil is severely compacted” |
| Moss | ”This area is too shady, too wet, or too acidic” |
Spraying herbicides addresses the symptom. Fixing the underlying issue prevents the weed from coming back.
Herbicide Safety Reminders
- Read the label. Every time. The label IS the law.
- Know your grass type. Some herbicides damage certain grasses (e.g., 2,4-D can harm St. Augustine at high rates).
- Temperature matters. Don’t spray when air temps exceed 85-90°F — volatilization causes drift damage.
- Don’t spray on windy days. Even “safe” herbicides kill plants they weren’t intended for.
- Wear PPE. Gloves, eye protection, and closed-toe shoes minimum.
Lawn Command’s TurfCheck AI identifies weeds from a photo and recommends the right treatment. The app also tracks soil temperature to time your pre-emergent perfectly. Download free for iOS →
