hoary cress
(Lepidium draba (L.) Desv)

Overview

Appearance

Lepidium draba is a perennial forb in the mustard family that can grow up to 2 ft. (0.6 m) tall.

Foliage

The leaves are soft, gray-green, 1.5-3 in. (3.7-7.6 cm) long with fine hairs and heart-shaped bases. The lower leaves tend to have more hairs than the upper leaves. The upper leaves clasp to the stem of the plant.

Flowers

Flowering occurs in early spring to early summer, when white, four-petaled flowers develop in clusters at the apex of the stem.

Fruit

The fruit are heart-shaped seed pods.

Ecological Threat

Lepidium draba invades rangelands, pastures, streambanks, and open forests primarily in the western United States, although it does occur in the East. It can form large infestations that can displace native species and reduce grazing quality. This plant is native to Central Europe and Western Asia and was first introduced into the United States in the early 20th century.

Resources

• Element Stewardship Abstract - The Nature Conservancy
• Federal Noxious Weed Disseminules of the U.S. - USDA-APHIS
• Weed of the Week - USDA Forest Service
• Weed Field Guide - USDA Forest Service

Selected Images

Maps

Invasive Listing Sources

• Alaska Noxious Weeds
• Alberta Weed Control Act
• Arizona Noxious Weeds
• California Invasive Plant Council
• California Noxious Weeds
• Colorado Noxious Weeds
• Idaho Noxious Weeds
• Iowa Noxious Weeds
• Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
• John Randall, The Nature Conservancy, Survey of TNC Preserves, 1995.
• Kansas Noxious Weeds
• Michigan Noxious Weeds
• Montana Noxious Weeds
• Nevada Noxious Weeds
• New Mexico Noxious Weeds
• Nonnative Invasive Species in Southern Forest and Grassland Ecosystems
• Ohio Noxious Weeds
• Oregon Noxious Weeds
• Pacific Northwest Exotic Pest Plant Council, 1998
• South Dakota Noxious Weeds
• Utah Noxious Weeds - Contain
• Washington Noxious Weeds
• WeedUS - Database of Plants Invading Natural Areas in the United States
• Wyoming Noxious Weeds

References