- Alliaria petiolata (= A.
officinalis) Cavara and Grande (Brassicaceae)
- 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
- 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.
- The concern surrounding A.
petiolata comes from its ability to aggressively invade a
woodland community and displace native grasses, herbs and
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
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