buckthorn

Buckthorn Management at River Bend Nature Center

River Bend's ongoing efforts to eradicate an invasive species

The Plant and the Problems

European (common) buckthorn (Rhamnus carthartica) is an invasive shrub species and is particularly troublesome in our region of southeastern Minnesota. Nearly every woodland and even many fields in this area have buckthorn infestations, which are detrimental to both the health of the forest, native wildlife, and even local agriculture. It was introduced as a landscape shrub, primarily for hedges and borders, and readily spreads through bird consumption of the berries and resulting dropping of the seeds elsewhere on the landscape. Click these links for more information on the identificationnatural history and ecological threats of this non-native species.

History in River Bend

Buckthorn control efforts in River Bend began in the early-to-mid 1990's and have intensified since 2000. Since much of River Bend is abandoned agricultural land in one form or another, most woodlands and brush lands across our 750 acres have at least some level of buckthorn infestation, whether it be patches of small saplings or acres of mature buckthorn "trees." As a small non-profit organization without a grounds maintenance staff, The nature center is dependant on the coordination of volunteers and outside crews to provide most of the labor, funded by various sources, and is very grateful for their assistance:

  • MN Conservation Corps
  • Carleton College Students
  • Faribault School Students
  • Shattuck-St. Mary's Students
  • Scout Groups
  • Church Groups
  • Local volunteers and other organizations

Control Mechanisms Employed at River Bend

River Bend uses a variety of methods to control or eliminate buckthorn on our grounds depending on the age of the plants, proximity to rare or sensitive features, and other varying conditions. The chart below sums up most of our efforts:

Stage of Growth RBNC Control Methods Photos
Young saplings
< 5 foot tall and
< 1/2 inch diam.
Hand pulled by various youth groups and programs. Root stocks shaken clear of soil, and remains are piled loosely for the benefit of birds and small mammals, erosion control, soil enrichment, and to reduce soil compaction caused by extra foot traffic required to remove them. Follow-up crews monitor sites every few years to remove any resprouts or missed plants. Spring, Summer, Fall.
Medium age 
3-8 feet tall and
1/2 to 1 inch
in diam.
Hand pulled by high school and college age student groups, often using tree planting bars to first loosen soil or a weed wrench. Pulled plants are handled similar to smaller plants as noted above, but also sometimes piled and burned. Sometimes only seed-bearing plants are targeted in large infested areas as an interim strategy until other efforts can be used. Summer, Fall.
Mature shrubs
10-20 feet tall and
> 1 inch diam.
Presently, mature plants are cut at the stump and the cut surface (cambium) treated with Garlon 3A (triclopyr) with a specially constructed wick applicator. Carefully followed pesticide application protocols to prevent spillage, harm to non-target species, and risk to the person applying the herbicide. Both the 8% concentration ("Brush-B-Gone") and the higher commercial concentration have been used with success. Trees are then left on site (often after cutting to smaller pieces) or removed depending on the location. We are contemplating the use of basal stem spraying in non-sensitive areas completely lost to mature buckthorn, but have not yet done so. Summer, Fall, Winter.
Special Notes
River Bend also engages in occasional deer management activities and native species plantings as part of our 3-pronged approach to habitat protection and recovery.
While used in other parks, prescribed fire is never used as a buckthorn control mechanism in River Bend since our Big Woods forest is not a fire-dependent community and as such a burn would negatively impact the herbaceous and woody species that occupy the same forest floor. (Fire is used to maintain our healthy prairie lands, however.)
The USDA is currently conducting research on the River Bend grounds to determine the effect of various herbicides commonly used for buckthorn control on adjacent non-target species. We hope to make the results public when available in a few years.
Other invasive plant species occasionally targeted with our habitat recovery efforts include tartarian honeysuckle, leafy spurge, and a few non-native thistles.

Help on the Horizon?

Efforts are underway to create a biological control mechanism for buckthorn, similar to the one developed a few years ago to control and eliminate purple loosestrife. Click this external link to read more about this exciting work that holds great promise in the battle against buckthorn in Minnesota and elsewhere.

Links to more information on the Web