Oxalis

The name Oxalis comes from the Greek word for acid – oxis – and refers to the acidity of the plant’s leaves. It’s also commonly known as shamrock or wood sorrel. Originally valued by gardeners as ornamental plants due to their bright flowers, some species have grown out of control and are now considered weeds.

Description
Oxalis is characterised by its clover-shaped leaves, which open during the day and close at night. At first, the leaves grow upwards but tend to droop the longer they grow. The flowers of the oxalis are often vivid and bold in colour, and the plant itself has fine hairs across its stem and leaves.

Habitat
Oxalis originates from South America and South Africa but the plant survives very well in the cooler temperatures of northern Europe and can overgrow in gardens, rapidly becoming naturalised and escaping to the wider landscape.

Availability
Oxalis corniculata regenerates each year, growing as an annual from seed that ejects from seed pods when ripe. The American Oxalis debilis doesn’t produce seeds regularly but does have bulbils which are easily spread when digging and can remain in the soil for years before leaving the dormant stage.

Species
The plant comes from the Oxalidaceae family and there are various species, including the Oxalis deppei, which has red flowers and a cross marking on its leaves (like a four-leaf clover) and Oxalis adenophylla, which has green leaves and pinkish purple, large flowers. Oxalis triangularis has reddish-purple leaves and pinkish white flowers and is known as the purple shamrock.

Care Tips
Oxalis responds best to plenty of light and cool temperatures which are kept consistent throughout the year. The plants need plenty of watering and feeding during the growth stage.

Did You Know?
Wood sorrel is edible and has been eaten by people for many thousands of years. It has been used throughout history to alleviate thirst and for its aphrodisiac properties.

The tubers have been long cultivated in Columbia for food and the leaves have been used to make a tea rich in vitamin C for sailors to drink to avoid getting scurvy.

References
http://apps.rhs.org.uk/advicesearch/Profile.aspx?pid=498
http://www.growsonyou.com/gardening/oxalis