Wood Sorrel - Oxalis acetosella L.

Wood Sorrel

Synonyms: Common Wood Sorrel, White Wood Sorrel, Cuckoo Bread, Cuckoo's Meat, Shamrock

Scientific Name: Oxalis acetosella L.

Family: Oxalidaceae (Wood-Sorrel family)


Europe, North America.


Oxalic acid and its potassium salts.


A walk in the woods, especially in spring in shady areas, can bring a welcome glimpse of vivid, fresh green – Wood Sorrel, which can reach a height of 15 centimetres. Despite its delicate nature, it has a powerful radiance which from April to June is emphasised by its white, red-veined, five-petalled flowers. A cell turgor pressure mechanism causes the heart-shaped, trifoliate leaves to fold up under some conditions. These include vibration, too much warmth or light, or the influence of the circadian rhythm. It is marvellous to see how the Wood Sorrel lets its leaves swing like pendulums in the morning, as if to greet the new day. As night approaches the leaves fold in upon themselves. The flowers, too, close at twilight and bow their heads as if the plant were settling down to sleep.

Wood Sorrel only feels at home in moist, semi-shady areas. No other native flowering plant thrives on so little light as this one. It achieves its full quota of photosynthesis with just ten percent of the daylight. It can even survive on just one percent daylight. In shady areas it carpets the ground by allowing its stems to branch and grow horizontally under the surface. The axillary buds occurring at intervals along these stems produce new tufts of leaves and side shoots in a kind of snowball system.

When its seeds are ripe, Wood Sorrel becomes a kind of firing range. Pressure in the seed capsules builds until it reaches as much as 17 bar. This pressure is enough to catapult the mature seed some 2.5 metres away from the mother plant. Sometimes a seed will land on a tree, where Wood Sorrel also feels quite at home and thrives. If it lands on moist soil, tissue in the seed swells, causing it to burst and propelling the seed once more through the air for as much as a metre.

Incidentally, Wood Sorrel not only grows the bright white flowers which open up to allow pollination by insects and bees. In summer and autumn, pinhead-sized flowers develop which remain closed and pollinate themselves. It is not known why the plant produces these flowers, which are known to botanists as cleistogamous, or hidden, flowers.

Interesting Facts

The generic name Oxalis is derived from the Greek oxýs = acid, sharp, and hális = salt. Acetosella, from the Latin acetum = vinegar or sour wine, also describes the sour character of the plant.

The first written mentions of Wood Sorrel as a medicinal plant are found in the manuscripts of the Greek physician and poet Nicander of Colophon (c. 150 BC).

In the Middle Ages the delicate plant was so popular as an ingredient of soups, salads and spinach that it was even cultivated in England in the 15th century. It remained popular until displaced by French Sorrel (Rumex scutatus L.), with which it is not related despite the similar common name. For a long time Wood Sorrel was the source of the oxalate used in textile dyeing, to remove ink and rust stains, to bleach straw and stearin and to clean copper and brass. Since it became possible to manufacture this salt synthetically, Wood Sorrel has lost its importance in this context. Moreover, obtaining oxalate in this way was a very time-consuming and expensive procedure. One of the main centres of the Wood Sorrel processing industry was the Black Forest region of Germany. It took about 75 kg of Wood Sorrel leaves to produce 500 grams of oxalic acid.

The Celts associated the sprightly Wood Sorrel with the leprechauns. Still today in Ireland there are representations of leprechauns always holding a Wood Sorrel leaf. Leprechauns not only enjoy playing tricks on humans, they are also extremely skilled artisans and guardians of the pot of gold at the end of the rainbow. To put the leprechauns in a good mood, the Irish used to place bread and milk or beer under the elder bush by the house, and would sometimes receive a little help with some handiwork in return. Whether the Irish shamrock was originally Wood Sorrel or Clover has never been definitively clarified. We discussed the issue in the plant portrait for Red Clover.

According to one folk myth, the cuckoo – a magical bird and messenger of the goddess of love and symbol of immortality – had to eat Wood Sorrel to get its voice. This is the origin of the common names Cuckoo Bread and Cuckoo's Meat.

The plant from another perspective

The delicate Wood Sorrel is a truly sprightly plant, whose leaf and seed movements make it appear to have a soul aspiring to something higher. As antipole its attachment to the earth is widely ramified. The axillary buds on the underground stems and the secretive cleistogamous flowers cower close to the earth and seem closed to all that is spiritual. Only the leaves and normal flowers of the Wood Sorrel allow it to overcome the congestion of the lower plant and open up. This gesture makes the plant a model of upbuilding activity for the human organism.

The plant in our products