Oxalis montana , or Sourgrass, is a flowering perennial plant in the wood sorrel family. native to eastern North America. It is usually found growing in colonies in cool, rich, moist woods, especially hemlock and spruce-fir forests. It is pretty and low-growing, but it can be weedy in disturbed areas. Sourgrass is a mounding plant with clover-like foliage and multiple flowers, with only one flower per stalk. The plant prefers moist soil and partial shade. The plant growth habit is a runner spreading indefinitely by rhizomes or stolons and the extensive root network helps it stabilize the soil. The leaves open and close in response to sunlight and the flower color ranges across the spectrum of white to pink depending on the elevation. At lower elevations the petals have stronger pink-purple veining. In addition to the showy blooms, the plant also has cleistogamous flowers that do not open, the purpose of these is to self-pollinate the plant. This plant has low toxicity and therefore edible in small amounts for humans and animals. It could be used on slopes or banks and in native pollinator woodland gardens. Diseases, Insects, and Other Plant Problems: No significant diseases or insects problems. More information on Oxalis .
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Clover-like compound, basal leaves with brown hairs long-stalked (though shorter than flowers stalks) with 3 leaflets. Shamrock-shaped leaves with three inverted heart-shaped leaflets, each about a 1/2 inch wide; slightly sour taste, leaflets close at night.
Flower color
Pink; White
Flower value
Long Bloom Season; Long-lasting; Showy
Flower form
Solitary
Flower shape
Radial
Flower size
< 1 inch
Flower detail
Blooms May through July with two types of flowers: 1) Solitary, dainty, nodding flowers 1/2 to 3/4 on an inch across, 5-parted oblong-elliptic petals, radially symmetrical, white, lavender, or rose with deep pink veins and a spot of yellow at the base of the petals that are notched at the tip. 2) Late in the season flowers without petals appear on curved stems, remain at the base of the plant and do not open, they self-pollinate.
Bloom time
Spring; Summer
Fruit color
Brown/Copper; Green
Fruit type
Capsule
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
Fruit a tiny erect rounded dry capsule with 5 sections that splits open when ripe to reveal 1 to 2 seeds per section.
Stem color
Green; Red/Burgundy
Stem detail
No stems as such. Rather, clumps of leaves grow to about 4 inches. Flower stems are green but reddish at the base.
Wildlife & Ecology
Native status
Native
Origin
Eastern Canada and United States
Distribution
Newfoundland, Nova Scotia, Manitoba, central and western New-England, Pennsylvania, Ohio, Michigan, Wisconsin, Minnesota, mountains of North Carolina and Tennessee.
Wildlife value
Attracts pollinators, provides wildlife cover and habitat, nesting, food source, and larval host.
Attracts
Bees; Butterflies; Frogs; Hummingbirds; Moths; Pollinators; Small Mammals; Songbirds
Small amounts of leaves, flowers, seeds, tubers/roots can be eaten raw are not dangerous they lend a sour taste to drinks and salads, hence the common name Sourwood.
Uses (ethnobotany)
In small amounts, the leaves, flowers seeds, and tubers/roots can be eaten raw or cooked or the plant parts can be used to make lemon flavored drinks, tea, and salads. Use sparingly, because all parts of the plant have a low amount of toxicity (oxalic acid) if ingested. The quantity of oxalic acid will be reduced if the leaves are cooked.
Landscape Use
Landscape location
Slope/Bank; Woodland
Landscape theme
Native Garden; Pollinator Garden
Garden tags
#native wildflower #native weed #perennial weed #NC native #problem for dogs #problem for horses #problem for cats #dainty #poisonous #woodland #weedy
Problems & Resistance
Problems
Problem for Cats; Problem for Children; Problem for Dogs; Problem for Horses; Weedy
The leaves contain oxalic acid that, taken in large amounts, can bind up the body's supply of calcium leading to nutritional deficiency. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution since it can aggravate their condition. All parts of the plant have toxic potential, although the possibility of serious effects is usually limited to ingestion of large quantities and there have been no documented cases in humans. Consuming Oxalis species can produce colic in horses, and kidney failure is possible if significant amounts are eaten. Caution: large quantities may cause trembling, cramps, and staggering as in grazing animal