Redwood Sorrel

Oxalis oregana

Physical Characteristics

Oxalis oregana is an evergreen Perennial growing to 0.2 m (0ft 8in). See above for USDA hardiness. It is hardy to UK zone 7. It is in leaf all year, in flower from May to July. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects. 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 can grow in full shade (deep woodland) semi-shade (light woodland) or no shade. It prefers moist soil.

Distribution

Western N. America - Washington to California.

Habitats

Woodland Garden Dappled Shade; Shady Edge; not Deep Shade; Ground Cover;

Edible Uses

Edible Parts: Flowers Leaves Edible Uses: Leaves - raw or cooked[118, 183, 257]. A acid, flavour, it is especially adored by children and makes an excellent addition to mixed salads[K]. The leaves can be harvested all year round[K]. A mass of the leaves and stems can be allowed to ferment slightly when they make a tasty dessert[183]. A sort of rhubarb pie can be made from the leaf stalks[183]. The leaf stalks are very thin - you would need an awful lot for a pie[K]. Use in moderation, see notes above on toxicity. Flowers - raw[K]. A pleasant acid flavour[K].

Medicinal Uses

Antirheumatic Ophthalmic Poultice A decoction of the whole plant has been used as a wash in the treatment of rheumatism[257]. The fresh juice of the plant has been used as eye drops to ease sore eyes[257]. A poultice of the wilted leaves has been used as a dressing on boils, sores and on swollen areas of the skin[257].

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].