Least Yellow Sorrel, Shady woodsorrel

Oxalis exilis

Physical Characteristics

Oxalis exilis is a ANNUAL/PERENNIAL growing to 0.1 m (0ft 4in) by 0.3 m (1ft). See above for USDA hardiness. It is hardy to UK zone 5 and is not frost tender. It is in flower from June to September. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects. The plant is self-fertile. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers dry or moist soil.

Distribution

New Zealand and Tasmania.

Habitats

Cultivated Beds;

Edible Uses

Edible Parts: Flowers Leaves Edible Uses: Leaves - raw or cooked[2, 46, 61, 105]. Added to salads, cooked as a potherb with other milder flavoured greens or used to give a sour flavour to other foods[183]. The leaves are available all year round unless the winter is very cold, they have a pleasantly sour taste[114], but are very small and fiddly to harvest[K]. The leaves contain about 86% water, 2.3% protein, 0.8% fat, 8.2% carbohydrate, 150mg calcium, 78mg phosphorus, 8mg iron, 0.6mg niacin, 78mg vitamin C, 6050µg beta carotene[173]. The leaves contain between 7 - 12% oxalate[218]. Use in moderation, see notes at top of sheet, Flowers - raw. A nice acid flavour and a pleasant addition to the salad bowl[K].

Medicinal Uses

Urinary Vitamin C The whole plant is anthelmintic, antiphlogistic, astringent, depurative, diuretic, emmenagogue, febrifuge, lithontripic, stomachic and styptic[147, 178, 218, 240]. It is used in the treatment of influenza, fever, urinary tract infections, enteritis, diarrhoea, traumatic injuries, sprains and poisonous snake bites[147]. An infusion can be used as a wash to rid children of hookworms[257]. The plant is a good source of vitamin C and is used as an antiscorbutic in the treatment of scurvy[240]. The leaves are used as an antidote to poisoning by the seeds of Datura spp, arsenic and mercury[218]. The leaf juice is applied to insect bites, burns and skin eruptions[218]. It has an antibacterial activity[218].

Known Hazards

The leaves contain oxalic acid, which gives them their sharp flavour. Perfectly all right in small quantities, the leaves should not be eaten in large amounts since oxalic acid can bind up the body's supply of calcium leading to nutritional deficiency. The quantity of oxalic acid will be reduced if the leaves are cooked. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition[238].