Creeping Woodsorrel

🌍 Non-native — naturalized; not a control priority

One of the most common garden and pathway weeds worldwide — a low, creeping mat that roots at the nodes, with clover-like leaves of three heart-shaped leaflets (often tinged purple-bronze) and small 5-petaled yellow flowers. Its slender seed capsules burst explosively, flinging seed several feet — which is why it turns up everywhere, including pot soil.

Historical use: This is another “weed” with a useful past. Useful Tropical Plants lists the leaves as edible raw or cooked, with a sour flavor and vitamin C, and summarizes medicinal uses from Chinese and Indian plant references. The sourness comes from oxalic acid, so this belongs in the “small amounts, not a staple” category, especially for people prone to kidney stones, gout, arthritis, or related conditions.

How it got here: No planned introduction story here — this one’s an accidental hitchhiker. Genetic and archaeobotanical work points to Southeast Asia as its original home, with the plant moving west along old trade routes and reaching Europe well before it ever crossed the Atlantic; nobody has pinned down exactly when or how it got to California, only that American records don’t go back past the 1800s. What keeps it going now is the nursery trade: its sticky, rough seeds cling to pots, tools, and irrigation lines, so infested container stock keeps reseeding new gardens even after the original patch is gone. It’s genuinely spreading on its own wherever that happens, not something anyone plants on purpose.

Commonly confused with: true clovers (Trifolium) and medics — but woodsorrel’s leaflets are heart-shaped (notched) and the flowers are yellow with 5 petals, versus clover’s rounded leaflets and pom-pom flower heads. Edible/sour but tart (oxalic acid).

Where seen near you: iNaturalist — Orange County

Sources: iNaturalist · Wikipedia · The origin of Oxalis corniculata L. (PeerJ) · UC IPM: Creeping Woodsorrel and Bermuda Buttercup · Useful Tropical Plants — Oxalis corniculata