Photo and text by Don Paulson

Wood-sorrel (Oxalis oregana)

In the coastal rainforests and west facing river valleys, such as the Hoh and Quinault valleys, extensive carpets of Oxalis oregana cover the moist forest floor. The masses of deep green "shamrock" leaves and attractive purple-veined flowers lend a fairyland appearance to the rainforest. You can find this plant in bloom from April to August.

Wood-sorrel normally holds its leaves horizontal in the filtered light of the forest floor, but at certain times will fold them sharply down. The plant will crease its leaves inward in response to direct sunlight, heavy rain, and during the night, all for apparently different reasons. It reportedly takes only 6 minutes to fold inward, an about 30 minutes to flatten out to a horizontal position again.

A small section of wood-sorrel will transplant readily to a shady Northwest garden. But beware - your shade garden will soon be carpeted by this aggressive, but attractive ground cover.

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