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Invasive Species - Crown Vetch - Coronilla varia L.
Crown vetch is a serious management threat to natural areas due to its
seeding ability and rapid vegetative spreading by rhizomes. This
aggressive exotic is now widespread along roadsides and natural areas.
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Common Names: crown vetch, purple vetch.
Native Origin: Europe, southwest Asia and northern
Africa
Photo: Beverly Turner, Jackson Minnesota,
Bugwood.org
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Description: Crown vetch is a perennial legume in the pea/legume
family (Fabaceae or Leguminosae. It can form large clumps from
creeping stems. The stems can be up to 6 feet long. Crown vetch
has rhizomes up to 10 feet long which allow the plant to spread
rapidly. The vegetative growth habit can rapidly cover and shade
out native vegetation. A single plant may fully cover 70 to 100
square feet within a four year period.
Compound leaves consist of 15-25 pairs of oblong leaflets.
Pinkish flowers are clustered in umbels on long stalks. The
flowers develop into narrow, flattened pods. The seeds are
reported to be poisonous. Crown vetch blooms from May through
August. It spreads both vegetatively through rhizomes and
through the dispersal of seeds. Habitat: Crown vetch has been
grown extensively in the northern two-thirds of the United
States for temporary ground cover, erosion control, and as a
green fertilizer crop. It is also used as a bank stabilizer
along roads and waterways. It occurs along roadsides and other
rights-of-way, in open fields and on gravel bars along streams.
It can survive in a variety of environmental conditions, but has
the highest yields in areas with 18 inches or more annual
precipitation. It can tolerate up to 65 inches of annual
precipitation, as well as withstand long periods of drought, but
cannot tolerate flooded or anaerobic soil conditions. It prefers
sunny, open areas, as it is intolerant of shade, and mature
plants can withstand minimum temperatures of -28°. |
F.
Megachilid Bee takes nectar at Crown Vetch Flower
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Distribution:
This species is reported from
states shaded on Plants Database
map. It is reported invasive in
CT, IN, KY, MD, MI, MO, NC, NJ,
OR, TN, VA, and WI.
Ecological Impacts: Crown vetch
is a serious management threat
to natural areas due to its
seeding ability and rapid
vegetative spreading by
rhizomes. This aggressive exotic
is now widespread along
roadsides and natural areas. It
becomes problematic when it
invades into natural areas, such
as grassland prairies and dunes,
where it works to exclude native
vegetation by fully covering and
shading native plants. It can
climb over small trees and
shrubs, and eventually form
large single-species stands.
Control and Management:
Manual- pulling out the entire
plant; mowing; prescribed
burning may be effective against
seedlings or in slowing the
spread of crown vetch, but will
not control large populations
Chemical- It can be effectively
controlled using any of several
readily available general use
herbicides such as glyphosate,
triclopyr, or clopyralid at
recommended label rates on the
cut stems and foliage. Follow-up
treatment with herbicide is
likely required to control any
surviving stems or new
seedlings. Follow label and
state requirements.
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Photo: Beverly Turner, Jackson Minnesota, Bugwood.org
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