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American bittersweet is a native woody climbing vine that grows in a wide variety of upland habitats -- woods, dunes, oak savannas and abandoned fields.
Leaves are alternate and finely toothed, rounded with a pointed tip and with a distinct petiole or leaf stalk.
The twining stem is brown with prominent lenticels and, if it has enough support, can grow several meters high.
Male and female flowers are on separate plants. White 5-parted flowers bloom in June, the female flowers always at the tip of a branch. Fruit is 6 to 8 mm across, turning yellow, then orange as it ripens in the
fall. At about the time the leaves drop, the 3 valves of the fruit split open (inset) and expose 3 dark orange or red fleshy appendages, each of which contains 1 or 2 brown seeds.
American bittersweet propagates by seed and by spreading stems and sprouting from its bright orange roots. Seeds are dispersed by birds and small mammals, although the fruit is not a choice food and usually
remains on the vine well into the winter. Use of the showy fruit in dried arrangements also contributes to dispersal.
Wisconsin has two bittersweets. The non-native Oriental or Round-leaved bittersweet, C. orbiculata, looks very similar but is invasive and easily out-competes American bittersweet and other native
species. Round-leaved bittersweet has broader leaves and its female flowers and fruit are only in the leaf axils, not at the branch tips.
Other characters, like fruit color don’t reliably distinguish the species. Before propagating or beginning a control program, be certain to distinguish the two species.
Origin of the name: Celastrus, Latin name for an unrelated tree; scandens, L., scando, to climb.
Range: Eastern N. Amer.
WI Range: Statewide
Common associates: Maples, oaks, juniper
Wetland Indicator Status: FACU
Coefficient of Conservatism: C = 4 (S&W), C = 3 (MI)
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