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garlic mustard

Alliaria petiolata (Bieb.) Cavara & Grande

USDA PLANTS Symbol: ALPE4
U.S. Nativity: Exotic
Habit: Herb


Synonym(s): garlic-mustard, hedge garlic, sauce-alone, jack-by-the hedge, poor man's mustard, jack-n-the-bush, garlic root, garlicwort, mustard root

Appearance
Alliaria petiolata is an herbaceous, biennial forb. First year plants are basal rosettes which bolt and flower in the second year. Plants can be easily recognized by a garlic odor that is present when any part of the plant is crushed.
Foliage
Foliage on first year rosettes is green, heart shaped, 1-6 in. (2.5-15.2 cm) long leaves. Foliage becomes more triangular and strongly toothed as the plant matures.
Flowers
Second year plants produce a 1-4 ft. (0.3-1.2 m) tall flowering stalk. Each flower has four small, white petals in the early spring.
Fruit
Mature seeds are shiny black and produced in erect, slender green pods which turn pale brown when mature.
Ecological Threat
Alliaria petiolata is an aggressive invader of wooded areas throughout the eastern and middle United States. A high shade tolerance allows this plant to invade high quality, mature woodlands, where it can form dense stands. These stands not only shade out native understory flora but also produce allelopathic compounds that inhibit seed germination of other species. Alliaria petiolata is native to Europe and was first introduced during the 1800s for medicinal and culinary purposes.


Identification, Biology, Control and Management Resources

Nonnative Invasive Plants of Southern Forests - USDA Forest Service
Biological Control of Invasive Plants in the Eastern United States - USDA Forest Service
Southeast Exotic Pest Plant Council Invasive Plant Manual - SE-EPPC
Invasive Plant Atlas of New England - University of Connecticut
Pest Alert - USDA Forest Service
Weeds Gone Wild: Alien Plant Invaders of Natural Areas - Plant Conservation Alliance
Element Stewardship Abstract - The Nature Conservancy
Fire Effects Information System - USDA Forest Service
Weed of the Week - USDA Forest Service
Plant Invaders of Mid-Atlantic Natural Areas - National Park Service and U.S. Fish and Wildlife Service
Fact Sheet - Ontarios Invading Species Awareness Program