Glossy or alder buckthorn (Rhamnus frangula)
Appearance: Tall understory shrub or small tree, grows up to 20' high, has 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).
Branches: Cut branch exposes yellow sapwood and orange heartwood.
Leaves: Alternate, think, and ovate or elliptic smooth, dark glossy, margins are not toothed; stay green late into fall.
Flowers: Inconspicuous, appear in May or June, clustered in the axils of leaves.
Fruit: Ripens progressively from a distinctive red to a dark purple in August and September. Seeds are viable for 2 - 3 years in the soil.
Roots: Extensive fibrous root system.
- Minnesota Conservation Volunteer magazine article The Trouble With Backyard Buckthorn
- Minnesota Noxious Weeds (MN DOT)