Last Updated on June 10, 2021
Wood sorrel — better known to some as sour grass or shamrock — is a common edible weed worth getting to know. You may find yellow wood sorrel (Oxalis stricta), creeping wood sorrel (Oxalis corniculata), or another type of edible wood sorrel growing in your garden right now, and it’s one of the tastier weeds you can eat. Find out how to identify wood sorrel or sour grass and how to use it.
WHAT IS WOOD SORREL OR SOUR GRASS?
Wood sorrel, or Oxalis, is a genus of flowering plant composed of over 500 species that grow around the globe. In Europe and parts of Asia, you’ll typically find Oxalis acetosella, and in North America we have numerous species, including Oxalis stricta (often called yellow wood sorrel or sour grass) and Oxalis corniculata (typically called creeping wood sorrel).
In the Pacific Northwest, you’ll find the purple-flowers oxalis oregana or Oregon oxalis (also known as redwood sorrel), while in the Rocky Mountains you’ll see oxalis violacea or violet wood sorrel.
Oxalis tuberosa grows an edible root known in South America as oca, a perennial vegetable to consider growing in your garden.
Some species of wood sorrels are perennial, while others are annual.
IS SOUR GRASS / WOOD SORREL EDIBLE?
Yes, wood sorrel is edible! Sour grass is a favorite foraged green, far more palatable to many than stronger-flavored plants like dandelions.
Wood sorrels are a terrific choice for beginner foragers, easy to identify and beloved by kiddos for its lemony flavor. Its signature heart-shaped leaves have led to one of its other nicknames, lemon hearts. You may also have heard it called sourgrass, common yellow oxalis, sheep’s clover, lemon clover, shamrock, or other regional variations.
The name sorrel derives from the old French for sour, while the botanical name oxalis comes from the Greek for acidic. Sour grass packs some wonderful tangy zing!
Sour grass is one of the wild greens we enjoy from our edible yard all season long. While not as early (or as aggressive) as creeping Charlie or Virginia waterleaf, it shows up not long after the cleavers and wild violets and well ahead of the purslane.
It tends to pop up in the garden beds, where we harvest it from time to time along with the veggies we planted, like lettuces, kale, spinach, and spaghetti squash. Harvesting edible wild plants like yellow wood sorrel is one of the strategies we use to get more food from our small space garden.
Permaculture is another. Find out more about permaculture principles to get more food from your yard with less work.
Foraging expert Samuel Thayer reports that all above-ground parts (leaves, stems, flowers, and fruits) of yellow wood sorrel are edible, though some are more tender than others. He reports the best flavor before flowering.
That sour flavor is a result of oxalic acid (hence the name oxalis), which can cause problems with nutrient absorption if taken in very large quantities, but it’s unlikely you’d eat enough yellow wood sorrel to experience difficulty. Oxalic acid is found in many common foods, including chocolate, coffee, beets, and dark leafy greens like spinach.
It’s also what gives rhubarb its signature sour flavor. You’re far less likely to overconsume wood sorrel than rhubarb crisp or rhubarb juice, though people with arthritis, gout, or a history of kidney stones are sometimes advised to limit their consumption of oxalic acid.
Wood sorrel is unrelated to French or garden sorrel (which is in the Rumex family), though it can be used in place of traditional sorrel in recipes. You can be sure you’ll find a lot more recipes out there calling for French sorrel than wood sorrels. I’ve included some suggestions for how to use sour grass and some links to wood sorrel recipes at the bottom of the post.
YELLOW WOOD SORREL BENEFITS & MEDICINAL USES
While most people enjoy sour grass as a pleasant nibble or addition to salads, it turns out, like so many other common wild plants we lump into the category of “weeds,” to have some useful medicinal properties as well.
Early twentieth-century herbalist Maud Grieve reports that in Europe wood sorrel had several traditional uses:
It has diuretic, antiscorbutic and refrigerant action, and a decoction made from its pleasant acid leaves is given in high fever, both to quench thirst and to allay the fever.
The old herbalists tell us that Wood Sorrel is more effectual than the true Sorrels as a blood cleanser, and will strengthen a weak stomach, produce an appetite, check vomiting, and remove obstructions of the viscera.
The juice used as a gargle is a remedy for ulcers in the mouth, and is good to heal wounds and to stanch bleeding. Sponges and linen cloths saturated with the juice and applied, were held to be effective in the reduction of swellings and inflammation.
In the Peterson Field Guide to Medicinal Plants and Herbs, Stephen Foster and James Duke report that in North America, the leaves of creeping wood sorrels were chewed for nausea, mouth sores, and sore throats and also used as poultices for sores and ulcers. A tea brewed from the leaves were used for fevers, scurvy, and urinary infections.
The Native American Ethnobotany Database includes uses for several species of wood sorrel by the Iroquois, Cherokee, Menominee, and others for sores, eye complaints, fever, and several other uses.
WOOD SORREL OR SOUR GRASS IDENTIFICATION
Sour Grass or Wood Sorrel vs Clover
Often mistaken for clover, yellow wood sorrel has attractive trios of heart-shaped leaflets rather than the rounded leaves clovers have. Clover is also edible, though, so not a huge problem when it’s mistaken for sour grass.
Wood sorrels in warmer climates may have more angular leaves, like Oxalis latifolia, pictured below.
The flowers of wood sorrels and clovers are also completely different, as you can see in the photos below. Yellow wood sorrel and creeping wood sorrel have delicate yellow flowers with 5 petals, while clover flowers have more of a pom-pom shape. Oxalis acetosella flowers are white with pink streaks. Other species have violet or pink flowers.
Wood sorrel’s leaves are generally green, but they can be tinged with light purple. They close up at night and reopen in the morning.
Yellow wood sorrel and redwood sorrel typically grow about 8 inches tall, while creeping wood sorrel, as its name suggests, stays closer to the ground. Some species of wood sorrels get considerably larger. European wood sorrels (Oxalis acetosella, pictured below) can get up to a foot tall.
Sour grass produces elongated seed pods that resemble tiny bananas. They send ripe seeds flying impressive distances when touched, helping them spread more widely in your garden.
HARVESTING SOUR GRASS
Sour grass is most easily harvested by snipping with scissors, leaving the roots intact. This method has two advantages: 1) You don’t disturb the soil, which helps to protect its structure and the invisible web of microbial life beneath it, and 2) The leaves will regrow, allowing for multiple harvests each season.
If you’re in the garden weeding, you can also pinch off a stem and nibble the tops for a refreshing snack, or if your yellow wood sorrel is competing with crops you value more, pull them up by the roots and chomp off the top before throwing them in your compost.
Younger sour grass stems can be eaten, but older ones can get tough. Strip off the leaves before using if you have a thicker, tougher stem.
Sour grass’s delicate leaves don’t keep well, so plan to use them right away or place in an airtight container in the refrigerator and use as soon as possible.
HOW TO USE WOOD SORRELS OR SOUR GRASS
Beyond its use as an easy and refreshing snack in the garden or on the hiking trail, yellow wood sorrel can be used in the kitchen in many of the same ways as garden or French sorrel, a popular herb that grows in shade.
♦ Wood sorrel’s pleasantly sour flavor makes it a lovely addition to salads, where its tiny edible flowers add a pretty pop of yellow. Use in green salads, potato salads, or grain salads like this adaptable wild rice salad. The little heart-shaped leaves and yellow flowers would be a fun addition to fruit salad also.
♦ You can add sour grass to your favorite smoothie recipe for some wild nutrition and lemony flavor. (Purslane is great in smoothies, too. Here’s my recipe for anti-inflammatory smoothie with purslane. Sub in some sour grass and see what you think.)
♦ A little sour grass can be added to cooked dishes like soups, frittatas, or casseroles, where a little acidity is welcome.
♦ Blended with butter, sour grass works well on baked or roasted fish.
♦ You can brew a lemony-tasting tea by steeping yellow wood sorrel in hot water, roughly 1/4 cup per 8 ounces of water. Chopping your sour grass first may help to release more of its flavor, or you can run the whole mixture through a blender before straining. Try in a homemade sun tea on its own or with other foraged herbs. Sour grass would be outstanding with borage or elderflower.
♦ Wood sorrels can be used in recipes calling for French or garden sorrel, though gathering it in sufficient quantities may take awhile.
WOOD SORREL RECIPES
♦ Eating weeds isn’t as out there as you might think. Food and Wine has a recipe for a scallop dish flavored with sour grass!
♦ Gather Victoria makes cream tarts with sour grass.
♦ Eating Pansies has a recipe for a strawberry and wood sorrel salsa.
♦ Escarpment Kombucha uses woodsorrel syrup in their gimlet recipe.
Have you tried yellow wood sorrel or another wood sorrel species? What do you like to do with it?
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Photo credits: Jon Sullivan, 6th Happiness, Carabo Spain, Hans Braxmeier, Couleur, anfehoe
Susannah is a proud garden geek and energy nerd who loves healthy food and natural remedies. Her work has appeared in Mother Earth Living, Ensia, Northern Gardener, Sierra, and on numerous websites. Her first book, Everything Elderberry, released in September 2020 and has been a #1 new release in holistic medicine, naturopathy, herb gardening, and other categories. Find out more and grab your copy here.