There are many species of sorrels found through out the world. Sorrel is an herb used in soups and sauces, but it can be the main meal. East Slavic, Polish, Lithuanian, and Yiddish people make sorrel soup, considered a kosher food in the Jewish religion. Sorrel leaves are also eaten fresh as in salads. The taste is slightly tangy due to the presence of oxalic acid, which is found in many dark green leafy vegetables like spinach, and in rhubarb, black pepper, cocoa, most nuts, many berries, and beans.
Oxalic acid in high concentrations is actually toxic to the human body. It combines with positively charged metal ions to form oxalates that can crystallize and form kidney stones even in smaller concentrations, and shouldn't be eaten by people prone to the formation of kidney stones. It can also inhibit the absorption of calcium.
Because of its ability to interact with metal ions like iron, calcium and magnesium, oxalic acid is used as a cleaning agent in dry cleaning, rust elimination, and pre-treatment of stainless steel. It is used in tanning leather, restoring wood products and polishing stones. Oxalic acid acts as a mordant in the dyeing process, making the dye stick to the cloth. You can even use oxalic acid to remove warts.
Wood sorrel looks a little like clover. The species that is native to the Northwest is commonly called Redwood sorrel; its Latin name is Oxalis oregana. As indicated by its Latin name, Redwood sorrel was first noticed by European-Americans in Oregon on the Lewis and Clark expedition in March of 1806. It tends to carpet the forest floor, particularly in redwood forests, but also under Douglas-firs and other conifer forests.
Redwood sorrel make a nice landscaping addition in shady areas, but if you don't want it everywhere, you'll need to weed it often since it spreads quite easily. It isn't a common herbaceous plant in Seattle any more since forests were cut down to build the city; regenerating forests to their former complexity will take a couple of hundred years if left to nature by itself. But you might see some in some of the forests where restoration is taking place with the help of volunteers. These pictures were taken next to Camp Long Lodge in the Alva Long native plant memorial garden established in 1998.
