What is shepherd's purse?

Shepherd’s purse identification comes down to the seed pods: flat, heart- or triangle-shaped pouches lined up along the stem, said to look like the leather purses shepherds once carried. It’s a winter annual in the mustard family from Europe and western Asia, now found across Pennsylvania and much of the world.

It sprouts in fall, sits through the winter as a flat rosette, then flowers and drops seed early in spring, often before you’ve started mowing. By early summer it’s dead and gone, leaving a crop of seed behind for next year.

Shepherd's purse identification: what to look for

• Rosette: a low circle of leaves, 2 to 4 inches long, that can be deeply lobed like dandelion leaves or just wavy-toothed. They’re covered in fine, often branched hairs that give them a slightly gray look.
• Flower stems: one or several slender, branching stems 6 to 18 inches tall, with a few small, arrow-shaped leaves that wrap around the stem.
• Flowers: tiny, white and four-petaled, clustered at the tips of the stems. They keep opening at the top while pods form below.
• Seed pods: the giveaway. Flat, notched, triangular to heart-shaped pods sit on short stalks along the stem, each with many tiny seeds.
• Root: a thin taproot that pulls out easily from loose soil.

Where it grows in Pennsylvania

Shepherd’s purse shows up wherever there’s open soil in fall. That includes thin or newly seeded lawns, garden beds, vegetable gardens left bare over winter, the edge of a driveway, cracks in a walk and plants brought home from a nursery.

In central PA it’s often one of the first weeds to flower in March and April, along with henbit and chickweed. It’s a sign that your lawn or bed had bare spots the previous fall.

It isn’t picky about soil. It grows in heavy clay, sandy garden loam and the gravelly fill along a driveway, as long as it has light and a little open ground to germinate in. That’s why it so often appears the spring after a construction project, a new bed or a lawn that was torn up by equipment.

Shepherd's purse look-alikes

• Field pennycress is another mustard with white flowers, but its pods are round, flat and notched at the top like a coin, and crushed leaves smell like garlic or onion.
• Dandelion rosettes look a lot like shepherd’s purse early on. Dandelion leaves are smooth, ooze milky sap, and the plant makes a single yellow flower on a hollow stalk.
• Hairy bittercress has leaves split into small rounded leaflets and long, skinny pods that fling seeds when touched.

How to get rid of shepherd's purse

Good news: this is one of the easiest weeds on the list. Because it’s an annual, each plant you remove before it seeds is gone for good.

Hand and mechanical:

• Pull rosettes in fall or early spring. The taproot comes out easily, especially when the soil is moist.
• Hoe young plants in garden beds on a dry day so they wilt.
• Get plants out before the pods turn tan and split. Once pods are present, bag the plants rather than leaving them on the soil.
• Mowing low won’t stop it, because it flowers below the blade.

Cultural:

• Keep lawns thick. Overseed thin areas in late summer or early fall, the best time for cool-season grasses in Pennsylvania, so there’s no open soil when shepherd’s purse germinates.
• Mow at 3 to 4 inches during the season.
• Mulch beds 2 to 3 inches deep and plant a cover crop on vegetable beds in fall.

Herbicides: in lawns, common selective broadleaf combinations containing 2,4-D, dicamba, MCPP or triclopyr control it, and fall treatment of young rosettes works best. In established ornamental beds and turf, preemergence herbicides labeled for winter annual broadleaf weeds, applied in late summer before fall germination, can reduce new plants. Don’t use lawn products in vegetable gardens. Read and follow the product label every time; the label is the law. Check that the product is labeled for your site, whether that’s a lawn, a landscape bed, woods, a roadside or ground near water, where only aquatic-labeled products belong. Applying herbicide for hire in Pennsylvania requires a PA Department of Agriculture pesticide applicator certification, so bigger jobs belong with a licensed lawn-care or vegetation-management company.

Keeping it from coming back

Shepherd’s purse seed can stay in the soil for several years, and one plant produces plenty of it. A couple of years of pulling plants before they seed will make a real dent.

Fall is your key season. Close up bare soil with seed, mulch or a cover crop by September, and check beds again in early spring to pull anything that slipped through.

Be careful with tilling, too. Turning the soil brings buried seed back to the surface, so a vegetable bed that gets rototilled every spring and fall can keep a steady supply of shepherd’s purse going for years.

Questions we get about shepherd's purse

Similar weeds

Field PennycressThlaspi arvenseHairy BittercressCardamine hirsutaHenbitLamium amplexicaule