Rhamnus cathartica (Common Buckthorn): Minnesota Wildflowers

Rhamnus cathartica (Common Buckthorn)

Plant Info
Also known as:
Genus:	Rhamnus
Family:	Rhamnaceae (Buckthorn)
Life cycle:	perennial woody
Origin:	Europe
Status:	Invasive - ERADICATE! Noxious Weed Prohibited or Restricted species
Habitat:	part shade, shade, sun; moist to dry; woods, woodland edges, fence rows, waste areas,
Bloom season:	June - July
Plant height:	to 20 feet
Wetland Indicator Status:	GP: FACU MW: FAC NCNE: FAC
MN county distribution (click map to enlarge):
National distribution (click map to enlarge):

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Detailed Information

Flower:

Clusters 1 to 1½ inches across, appearing with leaf buds in the axils of new growth, along outer branches and branch tips, with about 10 flowers per cluster. Male and female flowers are typically on separate plants (dioecious). Flowers are yellowish green, less than ¼ inch across with 4 prominently spreading lance to narrowly triangular sepals, the males with four erect greenish stamens and the female with a single style, the tip 4-parted. Both male and female flowers have petals though they are too inconspicuous to easily observe with the naked eye.

Leaves and bark:

Leaves are mostly opposite or nearly so (occasionally alternate), simple, generally egg shaped, 1 to 2¼ inches long and ¾ to 1½ inches wide, rounded or tapered at base, the tip also rounded or tapered to a small abrupt point, the edges with small rounded teeth, surfaces sparsely hairy to hairy on the underside, on a ½ to 1¼ inch hairy stalk. The 3 or 4 lateral veins per side are strongly curved mid-blade towards the tip. Notably, the leaves do not change color in the fall, persisting green into late fall while everything else around them has shed their leaves for the season.

The trunk can be single or often multiple; a single trunk can be over 6 inches in diameter. The bark is dark gray to nearly black with a smooth, shiny surface that becomes scaly with age, thin with a bright yellow-orange cambium (layer of tissue just under the bark) and deep orange heartwood. New growth is green or brownish green, often smooth or with minute hairs, the second year twigs turning a dusty brown, older branches shiny gray green with scattered whitish, horizontal lenticels (pores).

The tip of of twigs often form a short, straight thorn with two elongated, brown scaly buds on opposite sides that curve in towards the tip and look similar to a deer hoof and from which the common name buckthorn is derived.

Fruit:

Fruit is a berry that ripens from dull green to shiny black, about ¼ in diameter on a short stalk, with purplish flesh surrounding 4 seeds in the center. This species' incredible propensity to proliferate across the landscape can be contributed to birds, in particular the robins, who love its fruit and spreads the seed everywhere through their droppings.

Notes:

Few species have introduced Minnesotans to the concept of invasive species like buckthorn. Even as recently as the early 1990's, it was still relatively infrequent across the broader landscape. Then it finally reached the point of exponential population growth and suddenly it was everywhere. At that time (and still today), many people were unaware of the threat until it had already cobbled up much of their fence rows, woodlots and even their backyard landscapes. It was listed as a restricted noxious weed in Minnesota in 1999. Control is difficult due to its shear numbers. Smaller trees and seedlings can be uprooted but it is nearly impossible to clear large acreages without resorting to herbicides to kill the roots systems of large established trees. Even after a thorough clearing, a persistent seed bank and new arrivals from surrounding unmanaged areas require long term monitoring and management strategies that must necessarily include period prescribed burns for large areas. It is discouraging that there is now an entire generation of young adults for whom a relatively open and diverse woodland is unfamiliar. While some scoffers insist this “new normal” will be accepted as well as our recently lost, diverse forest lands, I don't foresee the day when people will make plans to travel north in the autumn to observe the annual display of dark, impenetrable, drab green Mirkwood-like forests.

Dormant identification is important for this species as many control projects are undertaken in the winter months. In late fall and early winter the persistent green foliage is the most standout characteristic. Later look for the nearly opposite brown buds with the short thorn between them on the tip of twigs, and the blackish gray bark, often shiny on the branches but peeling and corky on the lower stem, the lenticels sparse and somewhat obscure. Scraping the thin bark reveals a distinctive bright yellow-orange cambium underneath. When pulled from the ground the shallow, very fibrous roots are black throughout. Native Prunus species may be present in buckthorn infested land and can be confused with buckthorn when dormant, particularly Black Cherry (Prunus serotina). The twigs of Black Cherry are lighter brown and more finely structured with small, alternate reddish brown buds and no thorns, where buds of Common Buckthorn are opposite or nearly so. The lower bark on younger cherry saplings can be black and peeling corky but the smaller branches are typically much shinier with often very prominent horizontal white lenticels, and the cambium underneath is greenish white when freshly scraped. Cut broken branches also give off a very strong bitter almond odor when cut or crushed.

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More photos

Photos by K. Chayka taken in Anoka and Ramsey counties. Photos courtesy Peter M. Dziuk taken at locations across Minnesota.

Comments

Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Deane - Park Rapids, Hubbard County
on: 2014-02-01 21:40:14

Buckthorn is widespread in the lowlands along the Fishhook River within and south of Park Rapids. You rarely see it in the woodlands to the north, but it looks like it has been thriving here for a long time.

Posted by: Starr - Minneapolis
on: 2014-07-12 14:54:37

All over Linden Hills area of Mpls. Neighbor has a mature tree-20ft tall-that leans over into our yard, dropping seeds that have us pulling hundreds of seedlings up each summer. Tough to pull and impossible to get rid of them all.

Posted by: chris - Bloomington
on: 2014-12-11 15:30:14

Lots, and lots and lots of buckthorne in Moir park, Harrison picnic ground, Nine Mile creek park and the national wildlife refuge. Often omes right back when cut out w/o something planted to take it's place in the ecosystem (I.E., summac or similar plant).

Posted by: Mary - Rosemount
on: 2015-09-14 10:24:00

In a development in Rosemount, the president of the Homeowners Assn. has made a rule that he likes buckthorn and he fines anyone who tries to take it out (he is backed by the board because they are afraid of him). Is there anything that can be done because the buckthorn is taking over the woods behind our houses? Any help would be appreciated. Thank you.

Posted by: K. Chayka
on: 2015-09-14 10:32:43

Mary, both glossy and common buckthorn are "restricted" noxious weeds in Minnesota, which means sale, transportation, or intentional propagation is prohibited, according to the MN Dept. of Agriculture noxious weed law. Under this classification, while there is no legal requirement that existing populations be controlled or eradicated, it is MDA's recommendation they be dealt with if at all possible. You might try contacting someone at the city for their take on it - maybe they can apply some pressure. Good luck.

Posted by: Bill - Andover
on: 2016-06-24 18:37:18

Mary, when it takes over your woods, it will be a big job. I wonder if your homeowners association pres. knows what it does to reduce property values. I just spent two summers, every weekend, killing buckthorn in my 40 acres. I'm finally getting ahead of it. There is a sneaky way to take it out if you can be back in the woods unnoticed. Look up "basal bark" application of triclopyr. You just paint the bottom 18 inches of the trunk. The buckthorn will grow its cambrium shut and turn brown in three weeks, and no one will be the wiser. Then, he can remove it himself. Focus on the female trees with berries first.

Posted by: Pat - Blaine
on: 2016-08-03 14:11:36

The woods behind my house are full of buckthorn. I get rid of 1000's of them every year but that isn't even enough to clear out behind my house. Most of my neighbors don't seem to concerned about it so it often a losing battle. One neighbors solution was to eliminate the woods behind his house. I am very close to an SNA. I border a natural area that both the city and county have sought to preserve what is left. There are many rare plant species and undisturbed areas right by me that I fear the buckthorn will spread into.

Posted by: Cassandra C - Champlin
on: 2017-11-02 20:49:03

We recently bought a house in Champlin, and the backyard borders a city park which is full of buckthorn. My yard itself also has quite a bit, which I will be removing very soon. Don't know what to do about the buckthorn on the city park side though...should I contact the local tree inspector to see if they would remove it? Or do I just have to deal with it?

Posted by: K. Chayka
on: 2017-11-02 21:13:01

Cassandra, you need to contact the landowner, in this case the city. If you want to remove the buckthorn they may well let you take on that task, but you need their permission to do so.

Posted by: steve - Otter Tail Co
on: 2018-08-03 16:21:52

I see this everywhere in central OTC, woodland, yards in town, lining lake drives, ditches... I've been cutting, pulling, spraying, and burning this monster from my yard for 3 years now. If there are plants in hell this is one of them.

Posted by: Brad johnson - Owatonna
on: 2019-06-08 22:37:53

I might have a buckthorn. Could anyone help me identify it ?

Posted by: Steve - Ontario,Canada
on: 2020-08-10 11:18:31

Thanks for putting together such a comprehensive understanding of the threat, how to identify buckthorn, and how to distinguish it from, for example wild cherry. Here in central Canada the invasion is on. I have a wooded 1/2 acre and it is growing well along the edges. We do have wild cherry and of course want to keep the forest diversity going so would hate to lose the young ones due misidentification. Happily our neighbours are also interested in ridding this pest, the cooperation is high and I expect we will be clear of the worst of it in 3 yrs. The images and descriptions on this site are the best I've come across. Good luck in your efforts Minnesota!

Posted by: CPepin - Two Harbors
on: 2021-06-16 21:30:23

I was surprised to see Common Buckthorn in a wooded area on resort land just south of Two Harbors.

Posted by: Brady - Todd Co
on: 2021-11-10 20:30:43

The apparent explosion of this plant this year across MN (Seems to, to me anyway) tells me we need some sort of law requiring its management or a change in noxious weed classification to remove it immediately. Especially with stubborn property owners, and oddly enough, some cities, not allowing folks to remove this plant from parks and public areas.

Posted by: John Dahlseng - Lowry
on: 2022-07-08 12:16:06

If a buckthorn bush or tree with green berries is cut down and divided into small segments will the seeds in the the berries be viable? The plant is a re-sprout of a tree that was cut down a few years ago for powerline clearance and was cut down and divided into segments on 07-05-2022.

Posted by: K Chayka
on: 2022-07-08 21:39:43

John, immature fruit can continue ripening as long as it is still attached to the plant. It may not all mature but some very well could.

Posted by: Domini Brown - Twin Cities
on: 2023-06-26 13:52:45

University of Minnesota researchers recently published a paper stating that common buckthorn seeds only live in the soil for 1 or 2 years, not 6 years as commonly thought. Reference article: https://mitppc.umn.edu/news/uprooting-decades-buckthorn-management-practices-no-long-lived-seedbank. Related paper: https://doi.org/10.1007/s10530-023-03113-4.

Posted by: Cheryl - East side neighborhood of Bald Eagle Lake
on: 2023-06-29 13:51:30

I have been pulling buckthorn for over 25 years. It keeps reappearing due to neighbors not being aware that their trees are female. The birds ear the seeds then crap them in my yard wherever they can perch. Usually in the lilac bush row so finding them before they take deep root hold is difficult.

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