Free homeowner weed ID guide

Missouri Weed Identification Cheat Sheet

A quick-reference printable guide to 16 of the most common lawn weeds in St. Charles County. Stop guessing — identify the weed, understand how it grows, and know how to control it.

Covers the weeds homeowners actually see in Missouri lawns
Visual cues: leaf shape, flower color, growth habit, season
Includes control method cheat codes for each weed type

Printable weed ID reference

Your Missouri Weed ID Cheat Sheet

These 16 weeds are the most common intruders in St. Charles County lawns. Use this guide to identify what's growing, understand its lifecycle, and decide how to handle it. Print this page or save it for the next time you spot something unfamiliar.

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Broadleaf Weeds

🌼

Dandelion

Taraxacum officinale

Leaf Shape: Deeply toothed, hairless leaves in a flat basal rosette
Flower: Single bright yellow flower, 1–2 in., on hollow stalk
Growth: Taproot 6–18 in. deep; perennial, flushes spring + fall
Control: Dig entire taproot, or spot-treat with broadleaf herbicide in fall

🍀

White Clover

Trifolium repens

Leaf Shape: Three rounded leaflets with pale white chevron pattern
Flower: Round white, sometimes pink-tinged, pom-pom flower heads
Growth: Creeping stolons root at nodes; perennial, spreads fast
Control: Spot-treat in fall; improve soil nitrogen; thin turf invites it

💜

Creeping Charlie (Ground Ivy)

Glechoma hederacea

Leaf Shape: Rounded/kidney-shaped with scalloped edges, opposite on square stems
Flower: Small tubular blue-violet flowers in spring
Growth: Creeping stems root at every node; minty smell; thrives in shade
Control: Fall triclopyr treatment; fix shade + compaction; persistent

🌸

Henbit

Lamium amplexicaule

Leaf Shape: Roundish with scalloped edges, opposite; upper leaves clasp the stem
Flower: Purple-pink tubular flowers in whorls at stem tips
Growth: Upright from basal rosette; winter annual; square stems (mint family)
Control: Early spring post-emergent; pre-emergent in fall for next season

🌿

Common Chickweed

Stellaria media

Leaf Shape: Small oval pointed leaves, opposite on delicate hairy stems
Flower: Tiny white star-shaped flowers with five deeply lobed petals
Growth: Forms low dense mats; winter annual; roots at stem nodes
Control: Fall pre-emergent; early spring spot spray; thrives in cool wet conditions

🌺

Wild Violet

Viola spp.

Leaf Shape: Heart-shaped or kidney-shaped with waxy texture and prominent veins
Flower: Purple, blue, or white five-petaled flowers on low stalks
Growth: Clump-forming perennial with rhizomes; shade-loving; tough root system
Control: Fall triclopyr spot treatment; difficult to eradicate fully

🌵

Canada Thistle

Cirsium arvense

Leaf Shape: Lance-shaped with spiny edges; waxy, dark green surface
Flower: Small purple-pink composite flower heads, less prickly than bull thistle
Growth: Creeping perennial roots spread aggressively; forms colonies
Control: Fall systemic herbicide; repeated treatment needed for perennial roots

🌿

Broadleaf Plantain

Plantago major

Leaf Shape: Broad oval leaves with prominent parallel veins, in basal rosette
Flower: Tall slender green-brown spike, inconspicuous, rising above leaves
Growth: Taproot; perennial; thrives in compacted soil and high-traffic areas
Control: Improve soil compaction; broadleaf herbicide in fall; pull by root

🌼

Purslane

Portulaca oleracea

Leaf Shape: Thick, fleshy, paddle-shaped succulent leaves, alternate or clustered
Flower: Tiny bright yellow five-petal flowers at leaf nodes
Growth: Prostrate red stems radiate from center; summer annual; highly drought tolerant
Control: Hand-pull before seed set; pre-emergent in spring; remove all plant debris

🌸

Field Bindweed

Convolvulus arvensis

Leaf Shape: Arrowhead or spade-shaped leaves alternating on twining stems
Flower: White to pale pink trumpet-shaped flowers, 1 in. across
Growth: Twining or creeping stems; deep perennial root system; very persistent
Control: Fall systemic herbicide; deep root system requires multiple treatments

🌿

Carolina Geranium

Geranium carolinianum

Leaf Shape: Deeply divided, fern-like leaves with 5–7 palmate lobes
Flower: Small pink five-petal flowers in clusters; geranium-like scent when crushed
Growth: Winter annual; hairy stems; red coloration in cool weather
Control: Early spring post-emergent; pre-emergent in fall

🌱

Yellow Woodsorrel (Oxalis)

Oxalis stricta

Leaf Shape: Three heart-shaped leaflets, clover-like but with deeper notch
Flower: Small bright yellow five-petal flowers; sour taste when chewed
Growth: Upright or spreading; perennial; explosive seed capsules that eject seeds
Control: Spot-treat with broadleaf herbicide; hand-pull before seed pods mature

🌿

Lespedeza (Japanese Clover)

Kummerowia striata

Leaf Shape: Three oblong leaflets with parallel veins; smaller than white clover
Flower: Tiny pink-purple pea-like flowers at leaf axils
Growth: Wiry prostrate stems; summer annual; thrives in poor, acidic, dry soil
Control: Improve soil fertility; pre-emergent in spring; spot-treat with post-emergent

🔴

Prostrate Knotweed

Polygonum aviculare

Leaf Shape: Tiny blue-green oval leaves, alternate on wiry stems
Flower: Tiny inconspicuous white-pink flowers at leaf nodes
Growth: Forms dense flat mats; wiry red stems; thrives in compacted soil and cracks
Control: Fix soil compaction; pre-emergent in spring; spot-treat early

🥛

Spotted Spurge

Euphorbia maculata

Leaf Shape: Small oval leaves with a reddish-brown spot in the center
Flower: Tiny inconspicuous green-white flowers; white milky sap when broken
Growth: Prostrate mat-forming summer annual; sun-loving; spreads fast
Control: Hand-pull before seed set (wear gloves — sap irritates skin); pre-emergent in spring

Grassy Weeds & Sedges

🌾

Crabgrass

Digitaria spp.

Leaf Shape: Wide light green blades, ¼–½ in., with distinct mid-vein and membranous ligule
Flower: Finger-like seed heads rising above leaves in late summer
Growth: Sprawling clumps from central crown; summer annual; produces 150K+ seeds
Control: Pre-emergent at 55°F soil temp (Mar–Apr); post-emergent for active plants

🌾

Foxtail

Setaria spp.

Leaf Shape: Narrow, somewhat hairy blades with rough edges; no ligule
Flower: Bushy cylindrical seed head resembling a fox's tail
Growth: Summer annual; upright clumps; seed heads dangerous to pets
Control: Pre-emergent; mow before seed heads form; spot-treat with post-emergent

🌿

Yellow Nutsedge

Cyperus esculentus

Leaf Shape: Narrow, upright, glossy leaves in sets of three from triangular stem
Flower: Golden-brown seed head at top of triangular stem
Growth: Yellow-green, faster than turf; spreads via tubers underground; sedge, not grass
Control: Targeted sedge herbicide (not standard weed killer); fix drainage; persistent