Britt Slattery, USFWS
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Garlic Mustard
Alliaria petiolata
Origin: Europe
Background
Garlic mustard was first recorded in the United States
around 1868, from Long Island, New York, and was likely
introduced by settlers for food and medicinal purposes.
Distribution and Ecological Threat
Garlic mustard ranges from eastern Canada, south to
Georgia and as far west as Kansas and Nebraska. It occurs
in a wide range of moist to dry habitats including
roadsides, floodplains, and forest edges and interiors and
does not tolerate highly acidic soils. Garlic mustard
invades areas disturbed by human activities and appears to
be aided by white-tailed deer that prefer to eat native
wildflowers and leave garlic mustard untouched. Garlic
mustard displaces many native spring wildflowers such as
spring beauty (Claytonia virginica), wild ginger
(Asarum canadense), bloodroot (Sanguinaria
canadensis), Dutchman's breeches (Dicentra
canadensis), toothworts (Dentaria species) and
trilliums (Trillium species) that occur in the same
habitat. It is also credited with the decline of the West
Virginia white butterfly (Pieris virginiensis)
because chemicals in garlic mustard appear to be toxic to
the butterfly's eggs.
Britt Slattery, USFWS
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Description and Biology
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Plant: a biennial herb in the mustard family
(Brassicaceae); completes its life cycle within two
years and dies back by the second June, when it is
recognizable only by its dried fruiting stalks;
flowering plants range from 1 to nearly 4 feet in
height.
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Leaves: crushed leaves and stems have a garlic-like
odor; first-year plants appear as a rosette of
kidney-shaped leaves that stay green throughout the
winter; in its second year, the plant forms a shoot
which rapidly elongates and flowers in early spring.
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Flowers, fruits and seeds: clusters of small white
flowers in the axils of leaves along the stem; each
flower has four petals in the shape of a cross; fruits
are slender, erect capsules that contain a row of shiny
black seeds when mature.
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Spreads: a single plant can produce hundreds of seeds,
which are scattered up to several yards from the parent
plant.
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Look-alikes: toothworts (Dentaria species),
sweet cicely (Osmorhiza claytonii), wild anise
(Osmorhiza longistylis) and early saxifrage
(Saxifraga virginiensis).
Prevention and Control
Because garlic mustard seeds can survive for five or more
years in the soil, effective management of garlic mustard
requires a long-term commitment. Hand removal of entire
plants, including the roots, is effective for light,
scattered infestations. Cutting flowering plants low to
the ground in spring will prevent flowering and thus seed
production. Careful hand removal and bagging of plants
with mature fruits can be done from June through August.
Several herbicides are also effective for its control.
Researchers are investigating the potential for biological
control of garlic mustard.
Native Alternatives
Once garlic mustard has been removed, re-establish native
groundcovers such as:
wild ginger (Asarum
canadense)
Britt Slattery, USFWS
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lady fern (Athyrium
filix-femina)
Kenneth J. Sytsma, UWI
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evergreen wood fern
(Dryopteris marginalis or
intermedia)
Emmet J. Judziewicz, UWI
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foam flower (Tiarella
cordifolia)
Britt Slattery, USFWS
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creeping phlox (Phlox
stolonifera)
Britt Slattery, USFWS
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New York fern (Thelypteris
noveboracensis)
Britt Slattery, USFWS
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