Wood-sorrel blooms in April and May.

Photo: Amanda Scott

Scientific name: Oxalis acetosella

Other common names: Alleluia, Cuckoo’s Bread and Cheese, Granny’s Sour Grass

What to look for:

  • Family: Oxalidaceae (Wood-sorrel family)
  • Flowers: Purple-veined white flowers, up to 2.5 cm across, with five petals.
  • Leaves and stem: Distinctive yellowish-green trefoil leaves, purple-tinged on the underside, borne on long stalks.
  • Height: 5 to 10 cm.
  • Where: Common across the UK in woodlands and other shady habitats.
  • When: Flowers in April and May.
  • Habit: Upright.

In the spring, a woodland walk may well reward you with a delicate yellow-green glint tucked along the edge of the path or beneath a tree. These are the trefoil heart-shaped leaves of Wood-sorrel, gently folding along their middle. Nestled among them on long stalks are the lilac-veined white flowers, soft and pretty. Wood-sorrel is a common woodland plant, but no less a pleasure to see for that.

Like many other woodland plant species, Wood-sorrel grows and blooms in the spring, while the still sparse tree canopy is letting in enough light for woodland floor plants to thrive. It grows and spreads from rhizomes.

Wood-sorrel is edible, although can be toxic when eaten in large quantities because it contains oxalic acid. The leaves have a lemon flavour.  

Did you know…?

…Wood-sorrel is sometimes known as Alleluia across much of Europe. It is associated with Christian religious celebrations because it appears between Easter and Whitsun, and often features in fifteenth century paintings of the Crucifixion.

…At night, and in rain during the day, the Wood-sorrel’s flowers close and its leaves fold.

More information and references:

Mabey, R., 1997. Flora Britannica. Chatto & Windus, London.

Rose, F. and O’Reilly, C., 2006. The Wild Flower Key, 2nd edition. Frederick Warne, London.

Stace, C., 2010. New Flora of the British Isles, 3rd edition. Cambridge University Press, Cambridge.

Published: May 2015
Author: Amanda Scott
Photos: Amanda Scott