Inner bark yellow. Twigs often tipped with a spine. Leaves broadly elliptic, rounded to pointed at the tip, and toothed. Upper and lower leaf surfaces smooth. Upper leaf surface dark glossy green.
Leaves stay green late into fall, after all other leaves have fallen.
R. cathartica was introduced to North America as an ornamental shrub. It is native to Eurasia. The fruit causes a severe laxative effect, quickly distributing the seeds through birds. Common buckthorn invades mainly woodlands and savannas, although it may also be found in prairies and open fields. Once established buckthorn crowds or shades out native shrubs and herbs, often completely obliterating them.