How to Identify Common Lawn Weeds

Identifying a weed correctly before treating it is the most important step in weed control. Applying a broadleaf herbicide to a grassy weed produces no result. Applying a post-emergent herbicide to a weed that spreads only from seed, when the seed bank is the real problem, addresses symptoms rather than the source. This guide covers the most common lawn weeds in the US, organized by weed category to support the correct control decision.

Page Contents

The Three Weed Categories

Every lawn weed belongs to one of three functional categories, each of which responds to a different herbicide chemistry and control approach.

Broadleaf weeds: Plants with wide, net-veined leaves, typically two seed leaves (dicots). Most common lawn weeds are broadleaf. They are controlled by selective broadleaf herbicides containing 2,4-D, dicamba, MCPP, triclopyr, or combinations of these active ingredients.

Grassy weeds: Weeds that look like grass, narrow leaves with parallel veins and hollow round stems. Grassy weeds are not controlled by standard broadleaf herbicides and require either a pre-emergent (before germination) or a grassy-weed-specific post-emergent such as fluazifop or quinclorac.

Sedges: Plants that superficially resemble grasses but have solid, triangular stems (the classic identification is “sedges have edges”). Nutsedge is the most common lawn sedge. Sedges are not effectively controlled by broadleaf herbicides or standard grassy weed herbicides, and require specific active ingredients such as sulfentrazone, halosulfuron, or bentazon.

Common Broadleaf Lawn Weeds

Dandelion (Taraxacum officinale)

Type: Perennial broadleaf Identification: Deeply lobed leaves in a rosette at ground level, hollow stems, bright yellow composite flowers that mature into white seed puffs. Leaves are hairless and have teeth pointing toward the base. Deep taproot that can regenerate if broken. Season: Active spring through fall, most visible in spring when flower heads appear Control: Post-emergent broadleaf herbicide (2,4-D plus dicamba effective). Fall applications most effective because the plant translocates herbicide to roots efficiently as it stores energy for winter.

White Clover (Trifolium repens)

Type: Perennial broadleaf Identification: Three-leaflet leaves (trifoliate), often with a pale V-shaped mark on each leaflet. Round white flower heads. Creeping, mat-forming growth habit that spreads by stolons. Fixes nitrogen from the air, its presence often indicates a low-nitrogen lawn. Season: Active spring through fall Control: Post-emergent broadleaf herbicide. Clover is moderately resistant to 2,4-D alone, products containing MCPP or dicamba in combination improve control. Multiple applications may be needed for established plants.

Plantain (Plantago major / Plantago lanceolata)

Type: Perennial broadleaf Identification: Broadleaf plantain has broad, oval leaves with prominent parallel veins running to the base. Buckhorn (narrow-leaf) plantain has lance-shaped narrow leaves. Both form a rosette. Leaves are tough and rubbery. Season: Active spring through fall Control: Post-emergent broadleaf herbicide. Responds well to 2,4-D. Tougher to fully kill in established plants with dense root crowns, fall applications most effective.

Chickweed (Stellaria media / Cerastium fontanum)

Type: Winter annual broadleaf Identification: Small, oval, opposite leaves on trailing stems. Tiny white star-shaped flowers with five deeply cleft petals. Common chickweed (Stellaria media) has a single line of hairs along the stem. Mouse-ear chickweed (Cerastium) is fuzzier and more mat-forming. Season: Germinates in fall, grows through winter and early spring, dies as temperatures rise in late spring Control: Pre-emergent in early fall prevents germination. Post-emergent broadleaf herbicide in early spring while actively growing is effective.

Ground Ivy (Glechoma hederacea)

Type: Perennial broadleaf Identification: Round to kidney-shaped leaves with scalloped edges. Square stems (characteristic of the mint family). Small blue-purple flowers in spring. Spreads aggressively by stolons and is one of the harder-to-control perennial broadleaf weeds. Season: Active spring through fall Control: Triclopyr-containing herbicides provide better control than 2,4-D or dicamba alone. Products containing triclopyr plus 2,4-D and dicamba (such as Pennington UltraGreen weed and feed) target ground ivy more effectively. Multiple fall applications may be needed for well-established plants.

Henbit (Lamium amplexicaule)

Type: Winter annual broadleaf Identification: Small, rounded leaves with scalloped edges, attached directly to the stem without a stalk on upper leaves. Purple tubular flowers in spring. Square stems (mint family). One of the first weeds to flower in spring, the purple flower color is distinctive. Season: Germinates in fall, flowers in early spring, dies in late spring Control: Pre-emergent in fall prevents germination. Spring post-emergent broadleaf herbicide while in flower is effective. Full details in henbit: identifying and removing the purple weed.

Spurge (Euphorbia maculata / Euphorbia supina)

Type: Summer annual broadleaf Identification: Prostrate, mat-forming growth habit. Small oval leaves, often with a reddish central spot. Milky white sap when stem or leaf is broken, a reliable distinguishing characteristic. Stems radiate outward from a central tap root. Season: Germinates in late spring, grows through summer, killed by first frost Control: Pre-emergent prevents germination. Post-emergent broadleaf herbicide on young plants before they form a dense mat. Full details in how to kill spurge weed.

Wild Violet (Viola sororia)

Type: Perennial broadleaf Identification: Heart-shaped leaves with scalloped edges on long stems from a central crown. Purple, blue, or white flowers in spring. Spreads by both seed and underground rhizomes. One of the most herbicide-resistant common lawn weeds. Season: Active spring through fall Control: Triclopyr is the most effective single active ingredient for wild violet. Multiple applications in fall are typically required for meaningful control of established plants.

Common Grassy Weeds

Crabgrass (Digitaria sanguinalis / Digitaria ischaemum)

Type: Summer annual grassy weed Identification: Spreading, low-growing grass with wide leaf blades relative to lawn grasses. Light green to yellow-green color. Finger-like seed heads that radiate from a central point. Germinates when soil temperatures reach 55 degrees Fahrenheit consistently. Season: Germinates in spring, grows through summer, killed by first frost Control: Pre-emergent herbicide (pendimethalin, prodiamine, dithiopyr) applied before soil temperatures reach 55 degrees Fahrenheit. Post-emergent control of established crabgrass requires quinclorac or fluazifop-p-butyl in specific products.

Annual Bluegrass / Poa annua (Poa annua)

Type: Winter or summer annual grassy weed (depending on ecotype) Identification: Bright green, fine-textured grass with boat-shaped leaf tips. Small white seed heads visible even in mowed turf. Produces seed prolifically and quickly. Season: Winter annual ecotype germinates in fall and early winter; summer annual germinates in spring Control: Pre-emergent in early fall for winter annual ecotype (before soil temperatures drop below 70 degrees Fahrenheit). Ethofumesate provides some post-emergent control in cool-season turf.

Goosegrass (Eleusine indica)

Type: Summer annual grassy weed Identification: White, flattened stem base that gives the plant a silvery appearance at the crown. Wide leaf blades with prominent midrib. Zipper-like seed heads. More heat and drought tolerant than crabgrass. Often germinates two to three weeks later than crabgrass. Season: Germinates in late spring, grows through summer Control: Pre-emergent herbicide. Goosegrass is less responsive to pendimethalin than crabgrass, oxadiazon and dithiopyr are more effective pre-emergent options. Post-emergent control is difficult.

Common Sedges

Yellow Nutsedge (Cyperus esculentus)

Type: Perennial sedge Identification: Grass-like but with triangular stems (not round), shiny yellow-green leaves with a prominent midrib. Grows faster than lawn turf after mowing. Underground nutlets (tubers) allow it to persist and spread even when foliage is removed. Season: Most active in summer, particularly in wet or poorly drained areas Control: Requires sedge-specific herbicides: halosulfuron-methyl (Sedgehammer), sulfentrazone, or imazaquin. Standard broadleaf and grassy weed herbicides are ineffective. Full details in how to get rid of nutsedge.

Using This Guide for Control Decisions

Once you have identified the weed category and species, the control decision follows directly:

Annual weed (crabgrass, chickweed, spurge): Pre-emergent applied before germination is the most efficient prevention strategy. Post-emergent on young plants before establishment is the backup.
Perennial broadleaf weed (dandelion, clover, ground ivy): Post-emergent systemic herbicide applied when the plant is actively growing. Fall is often the best timing for perennial broadleaf control.
Sedge (nutsedge): Use a sedge-specific herbicide. Standard herbicides will not work.
Grassy weed (crabgrass, goosegrass): Pre-emergent before germination, grassy-weed-specific post-emergent on young established plants. Standard broadleaf herbicides will not work.

For pre-emergent herbicide selection and timing, the full guide is at how to use pre-emergent herbicides on your lawn.