Buckthorn is so common in southern Michigan and regions of the United
States and Canada that most casual observers arent aware they are
relatively new to those areas. In fact, its densities are such that in some
places its complete removal would make a significant change to the look of
IDENTIFICATION: Its a coarse shrub or small tree with
many low branches that support a rounded, bushy crown of crooked, stout
branches. The small trees may reach a height of about 6m and have blackish bark
which peels away as the tree gets older. Some of its branchlets end in short,
conspicuous spines. The leaves are simple and range from alternate to
subopposite to opposite in arrangement. The blade is 4-9cm long, ovate to
elliptic in shape, with finely serrated margins, 3-5 pairs of noticeable,
arcuate veins, an acute tip, and a short petiole. The winter buds are black to
dark brown, almost claw-shaped against the twig.
FRUIT: The fruits are a multiple of purplish-black, round
drupes that are about 6mm in diameter and contain 2-3 nut-like pits, each
enclosing a seed. They mature in August-September and are persistent throughout
the winter. The seeds are excreted by birds (which is the primary method of
dispersal), and young buckthorn seedlings are often found beneath bird perching
SITE: It is fairly shade-tolerant and grows on a variety of
sites, but favors moist, well-drained calcareous soils near streams or
riverbeds, open woodlands, fencerows and woods edges. It does not do as well in
very dry sites.
ORIGINS: Common buckthorn is a native of England, eastward
through Scandinavia and Russia, and on into western Asia. It is also found at
lower elevations as far south as Morocco and Algeria. It was introduced to
North America by people living in the eastern United States in the second half
of the 19th century, apparently for use as edging (introduction in eastern
Canadian cities soon followed). The plants tolerance of a wide variety of
soils and sites, its hardiness, and its dense growth and persistent greenery
made it ideal for widespread use in tall hedges.
AMERICAN RANGE: Once the plants became adapted to the conditions in North
America, they soon spread out from their planted sites. Human plantings, large
numbers of seeds, high seed vitality and rapid germination gave them a strong
competitive edge versus native species. Their tolerance to a variety of site
and light conditions have helped them expand widely. Currently, the range of
R. cathartica in North America is an area bounded by Saskatchewan,
Canada, in the northwest, Nova Scotia in the east, North Carolina in the
southeast, and northeastern Kansas in the southwest.
OF COMPETITION: The prolific nature of buckthorn makes it invasive in the
worst sense of the word. Once established in an area, it quickly becomes the
dominant midstory or understory shrub or tree in areas with conditions
favorable for its development, outcompeting many native species. Its heavy seed
production and strong vitality shut out other plants from growing beneath its
ERADICATION: In order to restore natural areas to a more
natural condition, a variety of methods have been used. Girdling, cutting,
cutting and painting the stumps with a Garlon 4 and oil mixture, or cutting and
painting the stumps with a Roundup solution and prescribed burning have all
been used with varying effectiveness.
recommended and effective method of eradicating buckthorn is a multistep
process. First, in fall or winter when surrounding plants are dormant, cut the
trees and paint the stumps within minutes of cutting with a 10-20% solution of
Roundup. Second, use repeated prescribed burns to knock back any resprouts from
the root collar, as well as to kill off the hundreds of seedlings that suddenly
have lots of sunlight with the demise of their parent. Of course, you must
establish a healthy population of replacement plants (preferably native) to
prevent the buckthorn from being reestablished following the cuts and burns.
One team in Wisconsin found that when a seeding of native grasses and forbs was
added, resprouting of buckthorn seedlings was limited by the sod created by the
native plants, and the fire continued to knock back the buckthorn seedlings
that did sprout (Scriver and Leach, 1998). Buckthorn is a tough customer, so be
prepared to do some consistent, engaged action against the intruder, and with
continued effort you can get your land back for more desirable native
Canadian Field Naturalist III(4), Archibold, O.W., D. Brooks and L.
Michigan Trees, Barnes, B.V. and W.H. Wagner, Jr., 1996.
Restoration and Management Notes 16(1), Scriver, B. and M.
Article reprinted from the Spring 1999 issue of the Ann Arbor Wild
Copyright © 1999 Wild OnesNatural Landscapers,
photos of common buckthorn, see the following web sites: