Cool weather seems to bring out all those cabbage relatives. Shepherd’s purse (Capsella bursa-pastoris) is no exception. One nice thing is that most crucifers are edible. What isn’t so nice is they all tend to get the same diseases.
Shepherd’s purse is that weed that sends out the flower stalk with small white flowers and little triangular seed pods. It has a ring of deeply lobed leaves at the base. This basal foliage is the best table fare, especially when young. I prefer it cooked to raw, but it is not one of my favorite wild greens.
The triangular to heart-shaped fruits temporarily irritate the skin of some people. They don’t bother me but I still don’t eat them. They’re bitter.
For centuries seeds have been used to treat intestinal infections and vision problems. Some people still chew seeds to improve their sight. Shepherd’s purse seeds are extremely high in vitamin A, which might explain skin irritations as mega doses of carotene sometimes cause that.
The most prevalent medicinal use is to regulate menstrual bleeding. The plant’s high vitamin K content could help explain that. Shepherd’s purse is also used late in pregnancy to stimulate uterine contractions and prevent post-partum hemorrhage. Like plantains, it has been used throughout history as a styptic to help heal wounds. Teas, foliage, and seeds reduce urinary tract irritation and are used as a mild diuretic. Always see a doctor before using medicinal herbs, especially if you are on medication.
Overseas, shepherd’s purse seeds and extracts have been employed as a substitute for quinine in treating malaria, and show insecticidal promise. They contain natural mucilage which is effective for killing mosquito larvae. The plant is used for that purpose in Africa.
Around here, shepherd’s purse grows on most disturbed sites from fall until early to mid-spring. It also springs up in lawns where turf has thinned. There are a few places where you should try to eliminate it. Keep it out of your garden if you plan to grow any cabbage, broccoli, cauliflower or any other member of the cabbage family.
Shepherd’s purse can carry a fungus disease called club root, which will spread to cultivated crucifers. The disease reduces yields and overall crop quality. Once in the soil, this slime mold can persist for 20 years.
Farmers are well aware of problems caused by weeds of this family. Rotating crops helps a lot, but once in the soil this pathogen can be challenging since it can persist so long. The disease is worse on wet acidic soils and shepherd’s purse handles those conditions well.
Some new fungicides show promise, but keeping fields free from this pathogen is the best and cheapest option. It’s definitely the way to go for home gardeners. Learn to recognize shepherd’s purse, wild mustard and pennycress and eliminate them from your vegetable garden site. Pennycress looks something like shepherd’s purse, but it grows later in the spring and seed pods are more round. Wild mustard has clusters of four-petal yellow flowers and long finger-like seed pods.
Ted Manzer teaches agriculture at Northeastern High School.