Garlic Mustard

Taxonomy:

• Alliaria petiolata (= A. officinalis) Cavara and Grande (Brassicaceae)

Origin:

• A. petiolata is of European origin and was probably introduced to the United States by early settlers. It was used as a vegetable for its high Vitamin A and C content, a garlic-flavored herb in cooking, and planted to prevent erosion. A. petiolata was also used for medicinal purposes, treating gangrene and ulcers.

Ecology:

• A. petiolata is a biennial herb most commonly found in woodland communities. Although A. petiolata grows most frequently in moist shaded soil, it occurs from full sun to full shade and in diverse soil moisture levels. Seeds germinate in early spring (April) creating very high seedling densities (up to 20,000 seedlings/m2), which decrease by approximately 50% by the end of May. Plants overwinter as rosettes, continuing growth throughout the winter. Plants that survive overwintering produce inflorescences the following spring, disperse seeds (average 165-868 seeds/plant in Ohio), and subsequently die. After dispersal, seeds remain dormant for 20 months.         
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Distribution and Spread:

• The first record of A. petiolata in the United States dates back to 1868 in Long Island, NY. By 1990, the distribution had increased to 29 states primarily in the midwest and northeast US. The mode of dispersal is unknown, but believed to be influenced by white tailed deer (Odocoileus virginicus) populations, where trampling exposes soil, allowing seed to surface and germinate.

Problem:

• The concern surrounding A. petiolata comes from its ability to aggressively invade a woodland community and displace native grasses, herbs and tree seedlings.

Previous Control Methods:

• Prescribed fires, herbicide application (Glyphosate) and stem cutting have all been proven effective but only short-term control methods for A. petiolata. Problems with these methods include: some infested sites are fire-intolerant communities, Glyphosate is a non-selective herbicide affecting all green vegetation and stem cutting is very labor intensive.
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	©2003 Bernd Blossey