The Illinois Exotic Weed Act prohibits
the purchase, sale, offer to sell, distribution or planting of
Japanese honeysuckle, multiflora rose, purple loosestrife, kudzu and
six species of buckthorn: common buckthorn, glossy buckthorn,
saw-toothed buckthorn, dahurian buckthorn, Japanese buckthorn and
"These prohibited plants present a real
danger to everything from the beauty of a backyard garden to the
native flora of our state," said Illinois Department of Natural
Resources Director Joel Brunsvold. "Exotics like buckthorn, kudzu
and purple loosestrife spread rapidly, degrade natural communities
and can cause serious harm to threatened and endangered plants and
Some varieties of the prohibited
species may be offered for sale under different names, such as
Japanese honeysuckle, which is sometimes labeled as Hall's
honeysuckle. Consumers should check the scientific names of the
plants to make sure they are not buying a prohibited species.
Information on the banned plants, including their scientific names,
can be found below.
Consumers who are aware of prohibited
plants available in Illinois can contact the Illinois Department of
Natural Resources Office of Law Enforcement at (217) 782-6431 or 1
(877) 236-7529 [1 (877) 2DNRLAW].
-- All exotic buckthorns were introduced to North America as
ornamental shrubs. Common buckthorn (Rhamnus cathartica) and
dahurian buckthorn (Rhamnus davurica) inhabit woodlands and savanna.
Glossy buckthorn (Rhamnus frangula) is found most frequently in
wetland communities, though it can spread to upland sites, including
roadsides and fields. Saw-toothed buckthorn (Rhamnus arguta),
Japanese buckthorn (Rhamnus japonica) and Chinese buckthorn (Rhamnus
utilis) are found less frequently but are also banned. All exotic
buckthorns produce a fruit that is readily eaten by birds. The
severe laxative effect of the fruits means a ready distribution of
seeds. Once established, exotic buckthorns crowd or shade out native
shrubs and herbs. Non-native buckthorns can be found throughout
Illinois but have been a particular problem in the northern
two-thirds of the state. The plants also act as a host for the
soybean aphid, posing a significant threat to agricultural
production in the state. Plant buyers and sellers are reminded that
the prohibition on the sale, possession, distribution and planting
of buckthorn extends to subspecies such as plants marketed as "Asplenifolia"
and "Columnaris." These are subspecies of glossy buckthorn (Rhamnus
frangula) and as such are prohibited in Illinois.
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-- Japanese honeysuckle (Lonicera japonica), introduced to the
United States in the early 19th century as a ground cover plant,
climbs and drapes over native vegetation, shading it out. The
aggressive vine's prolific growth covers and smothers preferred
vegetation, including understory shrubs and trees, resulting in
habitat loss for birds and other forest, prairie and grassland
-- Kudzu (Pueraria lobata) was first imported to the United States
from Japan in 1876 and was planted extensively in the southern U.S.
to control soil erosion. The fast-growing, fast-climbing woody vine
grows with dense foliage, smothering other plants. Kudzu's huge
roots reach a depth of 10-12 feet, making eradication difficult. The
Illinois departments of Natural Resources, Agriculture and
Transportation have teamed with the U.S. Fish and Wildlife Service,
U.S. Forest Service, Natural Resources Conservation Service, and
private landowners on a focused chemical treatment program to slow
kudzu's spread in the state.
-- Multiflora rose (Rosa multiflora) was introduced into Illinois in
the 1950s from eastern Asia for wildlife cover and food. The thorny,
bushy shrub soon spread and became a serious invader of agricultural
lands, pastures, roadsides and natural communities. It invades
prairies, savannas, woodlands and forest edges, forming thickets or
"living fences" that smother out other vegetation. It is a serious
pest species throughout the state and the eastern United States.
loosestrife -- Purple
loosestrife (Lythrum salicaria) was introduced to North America in
the1800s, rapidly expanding and reaching the upper Midwest in the
1930s. It has become a serious threat to native vegetation in
Illinois during the past 20 years. Purple loosestrife occurs widely
in wet habitats, such as marshes, bogs, fens, sedge meadows and wet
prairies, but it also occurs in roadside ditches, on riverbanks and
at the edges of ponds, lakes and reservoirs. A single stalk can
produce 300,000 seeds, which can remain viable even after 20 months
of submergence in water. Purple loosestrife lacks natural enemies in
the United States and quickly crowds out most native vegetation.
Department of Natural Resources