🍀 Wood Sorrel Oxalis acetosella
This is a guide, not a substitute for expert identification. Foraging guides - including this one - can contain errors. If you are not completely certain of an identification, do not eat it. Cross-check against at least two independent sources, and when in doubt, consult a local foraging expert or an experienced forager in person before eating anything wild.
A delicate, low-growing woodland plant with clover-like leaves and a sharp, lemony taste, used sparingly as a garnish or in salads; an indicator species for ancient woodland.
Identification
A small perennial, growing to around 10cm, forming loose carpets on the woodland floor. Leaves are trefoil (three-lobed), each leaflet distinctly heart-shaped with a smooth (not toothed) margin, fresh green above and often purplish underneath; leaves fold down and inward in low light or rain, reopening in sunlight. Flowers, borne singly on thin stalks April-May, are white with fine purple/lilac veining and a yellow centre, five petals, opening in daylight and closing at night. The whole plant has a distinctly sour, lemony taste when chewed, reflected in its Latin name (Oxalis = Greek for 'acid', acetosella = Latin for 'vinegary'). Prefers cool, damp, shaded, undisturbed ancient woodland with plenty of moss.
⚠️ Dangerous look-alikes - read this before picking anything
No toxic look-alike, but wood sorrel is very commonly confused with clover (Trifolium species) because both have three leaflets. The reliable distinguishing features, cross-checked across foraging sources: wood sorrel's leaflets are heart-shaped with a smooth margin and a visible central notch, while clover's leaflets are oval/rounder with a finely toothed edge and often a pale chevron marking; wood sorrel's flower is a single five-petalled white/lilac bloom on its own stalk, while clover flowers are dense, ball-like or globe-shaped clusters of many small pea-family florets. A definitive final check is taste: wood sorrel is sharply sour/lemony, clover is bland to mildly sweet - clover is not toxic either way, so this is a positive-identification aid rather than a safety-critical distinction. The genuine safety point is wood sorrel's oxalic acid content: eaten in small amounts (a handful of leaves as a garnish or in a salad) it is safe for most people, but oxalic acid binds calcium and in quantity is linked to kidney stone formation and can aggravate gout, rheumatism and arthritis. People with a history of kidney stones, gout, or significant kidney concerns should avoid regular or large intake. Note: this guidance is drawn from foraging and general health sources cross-checked together (e.g. Practical Self Reliance, Feral Foraging) rather than a specific NHS page - no dedicated NHS advisory on wood sorrel consumption was found, so treat the oxalic-acid caution as well-supported general herbal/toxicological consensus rather than a formal NHS position.
UK habitat
Widespread but localised across the UK and Ireland, restricted to damp, shaded, long-established (often ancient) woodland with moss cover; used as an ancient-woodland indicator species in central and southern England.
Legal notes
Picking leaves/flowers from wild wood sorrel is covered by Theft Act 1968 s4(3) - non-commercial picking of foliage/flowers from a wild plant is not theft. Don't uproot the plant without landowner permission (Wildlife and Countryside Act 1981 s13). Oxalis acetosella is not on WCA 1981 Schedule 8, but because it indicates ancient woodland and can be locally sparse, pick lightly and never strip a patch. See the full UK foraging law guide for the general rules.
- Woodland Trust - Wood sorrel (Oxalis acetosella)
- RHS - Oxalis acetosella (common wood sorrel)
- First Nature - Oxalis acetosella, Wood-sorrel
- Foraging Course Company - Wood sorrel (Oxalis acetosella) identification
- Practical Self Reliance - Wood Sorrel: Identification, Uses, and Benefits
- Howspruce - Wood Sorrel vs Clover: ID Guide