2026-05-13
What Weed Is This in My Lawn? The Five Most Common, by Leaf Shape
Lawn weed frustration is mostly category confusion. Broadleaf herbicides annihilate dandelions and clover, do nothing to crabgrass. Pre-emergents stop crabgrass before it sprouts but are useless once it's established. The species name is what tells you which bottle to buy.
The five that cause 80% of complaints
| Weed | Leaf shape | Growth | Category |
|---|---|---|---|
| Dandelion | Long, deeply toothed | Rosette flat to ground | Broadleaf perennial |
| White clover | Trifoliate (three leaflets) | Creeping mat | Broadleaf perennial |
| Crabgrass | Grass blades, flat | Star-shaped spreading clump | Grassy annual |
| Broadleaf plantain | Oval, deeply ribbed | Low rosette | Broadleaf perennial |
| Yellow nutsedge | Grass-like, glossy | Upright, faster than turf | Sedge perennial |
The category decides the treatment
| Category | What works | What doesn't |
|---|---|---|
| Broadleaf perennial (dandelion, clover, plantain) | Selective broadleaf herbicide (2,4-D + dicamba + MCPP); spot-spray glyphosate; manual taproot removal | Pre-emergent (it sprouts from existing roots, not seed each year) |
| Grassy annual (crabgrass) | Pre-emergent in early spring (prodiamine, dithiopyr); post-emergent quinclorac after sprouting | Broadleaf herbicide |
| Sedge (nutsedge) | Halosulfuron (Sedgehammer); never broadleaf herbicide | Broadleaf herbicide; most pre-emergents |
Telling the look-alikes apart
Crabgrass vs other grasses in your lawn. Crabgrass blades are wider and flatter than fescue or bluegrass, and it grows in a star pattern radiating from a single point. Stomp on it and it springs back; turf grass is more vertical.
Yellow nutsedge vs grass. Nutsedge is shinier, lighter green, and grows visibly faster than the lawn — you'll see it standing taller a day after mowing. The stem is triangular (roll one between your fingers). The old line: "sedges have edges, rushes are round."
White clover vs medic. Both have three leaflets. Clover leaves have a faint white V on each leaflet; medic does not, and medic leaflets have a tiny point at the tip.
Are any of these actually problems?
Honest answer: depends what you want. White clover used to be in every lawn seed mix — it fixes nitrogen, stays green in drought, and pollinators love it. Dandelions fertilize themselves and the soil. Plantain is edible and medicinal. None of these are killing your grass; they are filling spaces where your grass is thin.
The two genuinely aggressive ones are crabgrass and nutsedge. Crabgrass is an annual that drops thousands of seeds and outcompetes turf in summer. Nutsedge spreads via tubers and is extremely hard to remove once established.
The strategy that actually works
- Mow tall (3+ inches for cool-season grass, 2+ for warm-season). Taller turf shades out weed seedlings.
- Water deep and infrequent rather than shallow and often. Encourages deep roots and discourages shallow-rooted weeds.
- Overseed bare spots in fall — empty soil is where weeds win.
- Apply pre-emergent for crabgrass when forsythias bloom in spring. After that point, you missed it.
- Spot-spray broadleaves with a selective herbicide; don't blanket-spray the whole lawn.
When the identifier helps
If your weed doesn't match the five above — purple flower, succulent stems, twining vine, prickly stems — run it through the weed identifier. The next tier of common offenders includes purslane, henbit, chickweed, bindweed, and ground ivy, each with its own control approach. The general plant identifier handles the rest.
