Bittersweet, either of 2 unrelated woody vines: U.S. bittersweet (Celastrus scandens) and European bittersweet (Solarium dulcamara). The U.S. bittersweet grows up to 20 ft (6 m) in height, and has tiny greenish flowers and a woody stem. In late autumn yellow pods split open, displaying red and yellow waxen berries. European bittersweet is rarely more than 8 ft (2.4 m) high. Its flowers vary from violet to light blue and sometimes white. The vine produces poisonous berries and leaves. It is native to Europe and Asia.