Three heart-shaped leaflets that fold down like umbrellas at night, and lilac-veined white flowers that close in the rain
Wood sorrel — Oxalis acetosella.
Nature · Wildflowers & flowers
Wood sorrel
Native · flowers Apr–May · cool, damp, ancient woodland
Oxalis acetosella — Oxalidaceae
Wood sorrel is a dainty carpet-forming herb of cool, damp woods, with clover-like leaves of three heart-shaped leaflets and solitary white flowers veined in lilac. Leaves and flowers fold down at nightfall and in rain, and the sour taste of the foliage gives the plant its name. It is particularly associated with ancient woodland.
How to spot them
- ▸Three heart-shaped leaflets meeting at the stalk tip, pale green and sometimes purple-tinged beneath, folding down like tiny umbrellas at night
- ▸Solitary white flowers with five petals veined in lilac-purple and a yellow centre, on slender stalks above the leaves
- ▸Grows in creeping clusters on damp, shady, mossy ground and on tree stumps
- ▸Flowers close at night and in wet weather, bowing their heads
- ▸Look-alike: lesser trefoil (Trifolium dubium) — its leaflets are egg-shaped, not heart-shaped, and its flowers are small yellow pea-flowers
How to know it
Legend says St Patrick used its trifoliate leaf to teach the Trinity, which is why it is sometimes called a shamrock
Wood sorrel — though true shamrock is usually attributed to clovers.
Folk names for this woodland plant include Alleluia, sleeping Molly and cuckoo sorrel
Wood sorrel.
The leaves of this woodland herb taste sharp and lemony because of oxalic acid, which can be toxic in large quantities
Wood sorrel.
Its Latin name records the taste: 'acid' in Greek and 'vinegary' or 'sour' in Latin
Oxalis acetosella — wood sorrel.
One of the few herbs able to grow in the deep shade of conifer plantations, particularly associated with undisturbed ancient woods
Wood sorrel.
A clover-like white-flowered plant of damp woods whose look-alike, lesser trefoil, has egg-shaped leaflets and yellow flowers
Wood sorrel.
Quick-fire facts
- •Family Oxalidaceae; Oxalis comes from the Greek for acid, acetosella from the Latin for vinegary or sour
- •Flowers April to May, according to the Woodland Trust; tiny closed flowers the size of pinheads also form in spring
- •Common names include cuckoo sorrel, sleeping Molly and Alleluia
- •Oxalic acid gives the tangy, lemony taste; leaves go into salads, soups and teas, but large quantities can be toxic
- •Particularly associated with ancient woodland because it relies on undisturbed soil, says the Woodland Trust
- •Spring flowers give nectar and pollen to early insects; leaves are nibbled by slugs, rabbits and deer
- •Leaves fold back at night and flatten again at daybreak; flowers close at night and in rain
- •Associated with St Patrick and the Holy Trinity, hence sometimes called shamrock
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Sources
- Woodland Trust — Wood sorrel (Oxalis acetosella)