Identifying and foraging common wood sorrel. A common edible weed, often mistaken for clover or shamrock. Perfect for beginners.

Identification difficulty: Beginner

Happy St. Patrick's Day! I'm going to try and get this post up early so I can go out drinking :). I'm not Irish, but who does't love a good beer? (Note: I said a GOOD beer. Not that swill they dye green and pour out by the barrel-full!)

In honor of the occasion, I'd like to talk about how to identify common yellow wood sorrel, sometimes called the American Shamrock.

Wood sorrel isn't a shamrock, as a shamrock is a type of clover (Latin genus: Trifolium), and wood sorrel is part of the genus Oxalis. Then again, there is some confusion about what a shamrock actually is! You see,  we associate the classic "3 heart" shape with shamrocks, yet no clover actually has this shape. Clovers are all 3 ovals! Instead, sorrels (Oxalis species) have the 3 hearts.

So who knows, maybe wood sorrel really is a shamrock after all?

As I've mentioned before, wood sorrel holds a special place in my heart. It's the first wild food I ever ate, that I didn't harvest with my mother or one of my grandmothers. No member of my family ever pronounced it as safe, I never picked it with them. I watched other children enjoy it, and picked and ate it for myself. They called it lemon clover. I ate it without hesitation, rather a dangerous precedent when your "expert" is an 8-year old, but it all turned out all right in the end.

Anyway, wood sorrel is easy to identify, and grows throughout North America. It also tastes great, and is a very versatile ingredient in the kitchen, all-in-all, a perfect plant for beginners to forage.

One small note of caution: Oxalis species contain oxalic acid, and shouldn't be eaten by those with kidney or liver diseases, or by those with certain autoimmune diseases, like Rheumatoid arthritis. 

On to identification . . .

Wood sorrel identification - it's super easy!

If the North American or European plant has a "compound" leaf that looks like 3 hearts joined at the base of each heart, and each heart has a "crease" or a seam down the middle, then you have a wood sorrel/Oxalis. (I'm not 100% sure about plants on other continents)

All wood sorrels/Oxalis are edible, though some are more or less palatable than others. Some are large, some are small. Some can have pink, white or lavender flowers.

Common or yellow wood sorrel, Oxalis stricta, is the plant we are talking about today.

• It has a leaf shape as described above
• It's very delicate, with thin stems and leaves no more than an inch across. 
• It has yellow flowers, with 5 petals. (But you can ID and eat before it flowers)
• It produces long, narrow seed pods, tapered at both ends, which are square-shaped in cross-section. (Again, you can identify and eat before seeds form)
• It generally grows about 6" high, but can reach 12-14" in optimal conditions.

Yellow wood sorrel is found throughout the US and Canada, though it may be absent from more mountainous areas. 

Creeping yellow wood sorrel, nearly identical, also edible

Common yellow wood sorrel is nearly identical to Oxalis corniculata, the creeping yellow wood sorrel, except creeping sorrel doesn't grow as high, it spreads by "creeping" accorss the ground. Creeping yellow wood sorrel is found in every state. It's also edible.

Wood sorrel is available through nearly the entire growing season, from mid-spring (sometimes early spring) through early fall!

Wood sorrel has many common names, mostly used by children who love this little plant. Some I've heard are: lemon clover, lemon grass, sour grass, and sour clover; there are doubtless others.

Similar looking plants

The most likely plant to confuse with sorrel is black medic, related to alfalfa, and a more distant relative of common clover. Like wood sorrel, black medic (Medicago lupulina) has 3-part leaves and yellow flowers. But notice it has oval-shaped leaves, with only a very small indent in the top, leaf edges are also serrated. The flower is also different from that of sorrel. 

Black medic is generally considered edible, but should be eaten cooked, as it may have long-term damaging effects when eaten raw, in large amounts. It should also be avoided by pregnant women.

Members of the alfalfa family have 3-part, oval leaves serrated leaf edges. Some clovers also have serrated edges, but to be absolutely safe, beginners should avoid them. If you encounter another small, three-leaved plant, with smooth leaf edges, it's a safe-to-eat clover.

Either Hepatcia americana, or Anemone hepatcia.

The only potentially dangerous similar looking plant would be a Hepatcia or a woodland Anemone. (There are some studies which suggest that these two plant genera are actually the same.) From a foraging standpoint they should both be avoided, as they are toxic in large amounts. I've unfortunately seen them confused with both wood sorrel and clover, because their leaves have 3 lobes.

The important thing to remember is that clover and wood sorrel have compound leaves, which means the "leaflets" don't ever attach into one whole leaf, rather they just touch as the base. Hepatcia and Anemone have one simple leaf that has 3 deep lobes, but it's all attached as one piece. Hepatcia and Anemone flowers are most often purple or white, but can be pink or yellow.

Eating wood sorrel, nutrition and sustainability

The presence of oxalic acid gives wood sorrel a sour flavor, often compared to lemons. Much of this sour flavor is lost with high-heat cooking, so wood sorrel is best used cold, to keep is flavor in-tact. Add it to salads, desert sauces, smoothies, herbal butters and more! Wood sorrel is high in vitamin C.

Wood sorrel is a native plant, and provides nectar for bees, butterflies and other pollinators; it's important to not over-harvest.

Wood sorrel medicinal qualities

The sour flavor in wood sorrel helps promote saliva production, which is good for gum health.  Wood sorrel is considered to be effective as a mild fever reducer, and may help stimulate digestion.