How to identify common lawn weeds
Every lawn weed has a biological weak point -- a stage when it is most vulnerable to the right management approach. Knowing which weed you have determines whether you need a pre-emergent (applied before germination), post-emergent herbicide, or physical removal, and when to apply it..
Every lawn weed has a biological weak point — a stage when it is most vulnerable to the right management approach. Knowing which weed you have determines whether you need a pre-emergent (applied before germination), post-emergent herbicide, or physical removal, and when to apply it. Misidentification wastes money on the wrong product and the wrong timing.
Broadleaf weeds
Dandelion (Taraxacum officinale)
The most recognizable lawn weed. Per Penn State Extension, dandelion has deeply lobed leaves (the lobes pointing back toward the center, like teeth of a saw) in a flat rosette. A milky sap exudes when the stem is broken. Bright yellow composite flowers on hollow stems, followed by the familiar round seed head (pappus).
Dandelion is a deep-taproot perennial — pulling by hand requires getting the full root (at least 4–6 inches), otherwise it regrows. Per Penn State Extension, fall is the most effective time for post-emergent herbicide application because the plant is moving carbohydrates into the root, pulling herbicide along with them.
The feed-and-forget option
Osmocote coated prills feed for 6 months on a single application. Balanced N-P-K, won't burn roots. Read our full pick.
White clover (Trifolium repens)
Three round leaflets per leaf (occasionally four), often with a lighter "V" mark on each leaflet. White globe-shaped flowers. Per Penn State Extension, clover is a nitrogen-fixing legume — its presence in lawns was actually considered beneficial before herbicide companies began marketing clover as a weed in the mid-20th century. In lawns maintained without nitrogen fertilizer, clover patches often indicate nitrogen deficiency.
Management: Per Penn State Extension, three-way herbicides (2,4-D + MCPP + dicamba) or products containing clopyralid control clover. Regular nitrogen fertilization (3–4 lbs actual N per 1,000 sq ft per year) suppresses clover by favoring grass competition.
Ground ivy (Glechoma hederacea)
A creeping perennial with square stems — a distinguishing feature in the mint family. Round to kidney-shaped leaves with scalloped (rounded teeth) margins. Per Penn State Extension, ground ivy is one of the most difficult broadleaf weeds to control because it spreads by stolons (aboveground runners) as well as seed. It also tolerates shade better than most lawn grasses, making it particularly problematic under trees.
Management: Per Penn State Extension, herbicides containing triclopyr (with or without 2,4-D) are most effective. Fall application is preferred. Multiple treatments in consecutive years may be needed.
Common plantain (Plantago major) and narrow-leaf plantain (Plantago lanceolata)
Common plantain has broad, oval leaves (2–6 inches) with parallel veins, in a rosette. Narrow-leaf plantain has lance-shaped leaves. Both produce tall, narrow seed stalks. Per NC State Extension, plantain is a sign of compacted, poorly aerated soil — it thrives where lawn grasses struggle. Per Penn State Extension, core aeration and overseeding with competitive grass varieties reduces plantain pressure over time.
Chickweed (Stellaria media)
A cool-season annual weed. Small (0.5–1 inch), oval leaves and tiny white five-petaled flowers. Stems have a single row of hairs running along them — a useful magnifying-glass ID feature. Per Penn State Extension, chickweed germinates in fall, overwinters as a seedling, and sets seed in spring before dying in summer heat.
Management: Pre-emergent herbicides applied in late summer/early fall before germination. Post-emergent in fall before overwintered plants set seed. Per Penn State Extension, physical removal is effective because the root system is shallow.
Oxalis (Oxalis stricta)
Shamrock-like leaves with three heart-shaped leaflets (superficially like clover, but the leaflets are heart-shaped, not round). Yellow five-petaled flowers. Per Penn State Extension, wood sorrel (Oxalis) is commonly confused with clover, but the yellow flowers and heart-shaped leaflets separate them reliably.