Hairy Bittercress
Broadleaf weed
Hairy bittercress (Cardamine hirsuta) is a small, fast-growing winter annual in the mustard family. Gardeners and growers notice it because it seems to appear overnight in late winter and early spring, and because its ripe seed pods fling seeds several feet when disturbed, spreading it quickly through beds, lawns, and container plants.
How to identify it
Look for a low basal rosette of pinnately compound leaves, each with several small rounded leaflets and a slightly larger leaflet at the tip. The plant is only a few inches across at the rosette stage, then sends up thin flowering stalks 3 to 9 inches tall. Tiny white flowers with four petals sit at the stem tips, followed by slender upright seed pods (siliques) that stand above the flowers. Despite the name, the plant is only sparsely hairy, mostly on the lower leaves, and it grows from a shallow, fine root system.
Where it grows
It thrives in cool, moist conditions and disturbed or bare soil, showing up in lawns, landscape and vegetable beds, gravel, sidewalk cracks, and especially nursery and greenhouse containers. As a winter annual it usually germinates in fall or late winter, flowers in early spring, and dies back as weather warms, though it can complete a life cycle in almost any cool, damp stretch of the year. It spreads entirely by seed, and each plant can produce hundreds of seeds that are scattered explosively when the mature pods are touched.
Why it is a problem
Because it matures so quickly and self-sows aggressively, a few plants can seed an entire bed or container yard in a single season. It competes with turf, seedlings, and potted crops for moisture and space, and it is a common contaminant hitchhiking on nursery stock. The explosive seed dispersal also makes it hard to contain once plants are allowed to flower.
How to manage it
The most effective step is to pull or hoe plants while they are still small rosettes, before flower stalks and seed pods form, since removing them after seeds set only scatters more. The shallow roots make hand pulling easy, especially in moist soil, and bagging seeding plants rather than composting them helps break the cycle. A two to three inch layer of mulch in beds and containers blocks germination, and keeping turf dense and vigorous through proper mowing height, watering, and fertility leaves little bare ground for it to colonize. Cleaning tools, pots, and incoming plants and refreshing container media also cut down on reinfestation.
Commonly confused with
It is easily confused with other small mustard-family weeds such as shotweed and with young shepherd's purse, and its rosette can resemble that of wild mustards, but the rounded compound leaflets and tiny upright seed pods held above the flowers help set it apart.
General guidance for US lawns and gardens, focused on prevention and non-chemical control. For a confirmed identification and options specific to your area, contact your local Cooperative Extension office. Page updated Aug 4, 2026.