General: plant height: 10-50 cm tall. Growth habit: annual, from weak taproots. Stems: simple to branched, with short, star-shaped hairs.
Leaves: mainly in a basal rosette, lance-shaped, broadest toward tip, 3-6 cm long, stalked, almost entire to pinnately lobed with larger lobe at tip. Stem leaves smaller, alternate, stalkless and clasping, lance-shaped to oblong, mostly with shallow, sharp teeth.
Flowers: white, with 4 petals 1.5-4 mm long and sepals 2 mm long, on slender, spreading stalks that are 7-15 mm long. Many flowers in round clusters at first, but these are later elongated in fruit.
Fruits: pods triangular to cordate, strongly flattened, long-stalked, 4-8 mm long and 3-5 mm broad at the tip, with style about 1 mm long. Seeds numerous, not edged, with minute, net-like patterns.
Common as a weed in disturbed areas, roadsides, gardens etc., even to subalpine habitats, in all parts of MT. Also almost throughout the rest of N. America.
All parts of shepherd's purse are edible, but have a biting taste. They can be eaten raw or cooked. The young leaves, used before the plant comes into flower, make a fine addition to salads, and can be used as a cress and cabbage substitute, however they become peppery with age. The leaves contain about 2.9% protein, 0.2% fat, 3.4% carbohydrate, 1% ash. They are rich in iron, calcium and vitamin C. The young flowering shoots can be eaten, raw or cooked, as well. The seeds, raw or cooked, can be ground into a meal and used in soups etc., but are difficult to harvest and utilize since they are very small. The seed contains 35% of a fatty oil, which can be extracted and is edible. The seedpods can be used as a peppery seasoning for soups and stews. The fresh or dried root has been used as a ginger substitute.
Shepherd's purse is little used in herbalism, though it is a commonly used domestic remedy, being especially efficacious in the treatment of both internal and external bleeding, diarrhea etc. A tea made from the whole plant has medicinal properties that have been used to induce urination, check bleeding, lower blood pressure, cause tissue to contract, assist the flow of menstrual fluid, cause blood vessels to constrict, relax or dilate, cause increased activity of other agents, cells, tissues and organs, and has an agent that is effective against scurvy. The herb has been used for healing wounds, fresh cuts, etc., usually used as a poultice. A tea made from the dried herb is considered to be a sovereign remedy against hemorrhages of all kinds - in the stomach, the lungs, the uterus and more especially the kidneys. The plant can be used fresh or dried, for drying it is harvested in the summer. The dried herb quickly loses its effectiveness and should not be stored for more than a year. Clinical trials on the effectiveness of this plant as a wound herb have been inconclusive. It appears that either it varies considerably in its effectiveness from batch to batch, or perhaps a white fungus that is often found on the plant contains the medically active properties. The plant has been ranked 7th amongst 250 potential anti-fertility plants in China. It has proven uterine-contracting properties and is traditionally used during childbirth. The plant is a folk remedy for cancer - it contains fumaric acid which has markedly reduced growth and viability of Ehrlich tumor in mice. A homeopathic remedy is made from the fresh plant. It is used in the treatment of nose bleeds and urinary calculus.