Many people who profess to know nothing about wild plants forget that they enjoyed eating wood sorrel (Oxalis spp.) greens as children. It’s a common childhood experience and I can think of no better (or simpler) introduction to the pleasures of foraging.
No searching is needed to find wood sorrel. Our most widespread species are common yellow-flowered weeds of gardens and lawns. One species, Oxalis montana, is not a weed. It has white flowers striped with pink and it grows in even the darkest hemlock stands. Nor is care needed to time the harvest: wood sorrel greens remain tender throughout the season and can be gathered any time from mid-spring through the summer, and into autumn.
Our region’s sorrels all fit a pattern that even beginners can recognize. The low-growing plants have alternating, clover-like leaves on long stalks. Each of the three leaflets is creased along the mid-vein and notched at the tip, making it look like a folded paper heart. The only plants that look similar, the clovers, have rounded leaflets; the two can also be distinguished by looking at the leaf veins: wood sorrels’ branch off the mid-vein while clovers’ diverge in parallel rows like the barbs on a feather. Mistakes in identification are low-stakes. Clovers are also edible, and the first taste will serve to distinguish the two. Clovers have none of the sour flavor of sorrels.
Wild-food guides often have dire warnings about the oxalic acid in the plants interfering with calcium absorption and leading to renal and joint problems. While it is true that this acid can cause problems, the concentrations present in wood sorrel are low. Spinach and rhubarb seldom carry such warnings, yet they are also high in oxalic acid. Anyone eating occasional servings of any of these plants has nothing to fear. Besides, the oxalic acid (along with other acids) is the source of the plant’s distinctive flavor.
Sorrels require no preparation whatsoever.
Just pluck off a leaf and pop it in your mouth. The entire plant is edible, though the leaves are the most flavorful part. The sour flavor makes them a welcome addition to salads and soups. Wildfoods writer John Kallas even uses a sorrel sauce to flavor ice cream. Experiment with using them in dishes that call for lemon or vinegar. Some foragers prefer not to include the stems in their dishes because of their stringy texture. Rather than tediously plucking off the leaves, I chop the sorrel greens in a food processor, stems and all.
Easy to find, easy to recognize, ready to eat as soon as they are picked, and blessed with a lemony tang that nearly everyone enjoys, wood sorrels make a great introduction to wild foods for people of all ages.
Wood Sorrel Pesto
2 cups fresh wood sorrel
1 clove garlic
3 Tbsp walnuts or pine nuts
1/8 tsp salt
1/4 cup olive oil
1/4 cup grated parmesan cheese
Pour wood sorrel, garlic, walnuts, and salt into a food processor. Blend until fine. Add oil. Blend until smooth. Add cheese. Pulse briefly until incorporated. Serve over pasta.