The redwood sorrel (Oxalis oregano) is one of a species of low-growing perennials commonly called wood sorrels. This particular species of oxalis derives its name from the fact that it is a native of the western North American redwood forests. (It can also be found in Douglas fir forests.) The redwood sorrel ranges from southwestern British Columbia in Canada southward into Washington, Oregon, and California in the United States.
Just like most other members of its family, the redwood sorrel has large shamrock-shaped leaves. The bright green leaves, which grow on short stalks – heights vary from 2 to 8 inches – have purplish-colored undersides. In early- to mid-summer, it produces white flowers with purple streaks that have five petals and ten stamens. These give way to hairy, five-chambered, egg-shaped seed capsules filled with almond-shaped seeds. Redwood sorrels do not require a lot of light. (They do grow, after all, on the forest floor.) In fact, when the sun directly hits the plant, the leaves will curl downward. As the shade returns, the leaves open up again. (You can actually stand and observe this process.)
All species of oxalis tend to be rather invasive, and the redwood sorrel is no exception. If you decide to grow this attractive woodland ground cover in your own garden, do so in an area where it can be contained. If you do not have such an area or are unable to use root barriers, you might want to consider growing it in containers. Plant redwood sorrel in the early fall in rich, well-drained soil. It is best to plant redwood sorrel in clumps, because the tubers or rhizomes are just too tiny to try to plant individually. Plant 3 inches deep and 4 inches apart. Divide in the mid- to late-summer after they have finished flowering. After the leaves have died back in the fall, just clear away the debris. [Note: You may not want to toss the debris from any type of invasive plant, such as the redwood sorrel, into your compost pile. Throw it away instead.] Once you have established the redwood sorrel in your woodland or shade garden, you will find that it is an easy-care, hardy perennial. (Just be aware of its invasive tendencies.)
Other varieties in which you might be interested:
O. adenophylla: This is probably the most popular variety. It has grayish-colored leaves and silvery flowers.
O. enneaphylla: This variety has folded, silvery leaves and white flowers.
O. laciniata: Look for its narrow leaves and purple, veined flowers.
O. tetraphylla: This has brown-marked leaves and pink flowers. Look for the variety commonly known as ‘Iron Cross.’
One final note of interest: It is believed that Native American Indians sometimes ate the leaves of the redwood sorrel. It is also believed that they must have eaten them in very small amounts, since the plant is slightly toxic.
References:
Scarlett, Kay, pub. The Complete Garden Flower Book. London, England: Murdoch Books UK Ltd., 2001.
