Common buckthorn (Rhamnus cathartica)

Description:

Appearance: Tall understory shrub or small tree up to 20' high with a spreading loosely branched crown, often multiple stems at the base. Brown bark with elongate silvery corky projections (Caution: native plums or cherries have a similar bark). Female and male plants.

Branches: Cut branch exposes yellow sapwood and orange heartwood. Twigs often end in stout thorns.

Leaves: Alternate, sometimes opposite; broadly elliptic pointed at the tip, smooth, dark glossy and small-toothed. Leaves stay green late into fall.

Flowers: Inconspicuous, appear in May or June, clustered in the axils of leaves.

Fruit: Clusters of black 1/4 inch fruit ripen on female plants in August and September. Seeds are viable for 2 - 3 years in the soil.

Roots: Extensive fibrous root system.

Ecological Threat:

  • Aggressively invades oak forests, savannas, prairies and riparian woods, completely eliminating native plant diversity in the understory over time. It thrives particularly on well-drained soils.
  • Plants leaf out early and retain leaves late into the fall creating dense shade.
  • Seeds have laxative effect on birds who disperse them.
  • Introduced to North America as ornamental shrubs.
  • Common buckthorn is on the MDA Restricted noxious weeds list in Minnesota.

 

Control Methods:

Mechanical
Prescribed fire for seedlings

Pulling in small infestations (weed wrench)

Chemical
Cut-stump treatment with glyphosate; cut-stump or basal bark spray treatment around the stem with triclopyr

 

Minnesota Conservation Volunteer magazine article The Trouble With Backyard Buckthorn