Although many surveys of invasive plants have been conducted, relatively little research has been conducted on the biology of hybridization between invasive and native species. We hypothesized that interspecific hybridizations between the native bittersweet (Celastrus scandens L.) and the invasive introduced species (C. orbiculatus Thunb.) may be more vigorous and have less seed dormancy than C. scandens seedlings. To test this hypothesis, we performed controlled pollinations using C. scandens as the female parent and C. scandens or C. orbiculatus as the male parent. Although both the interspecific and intraspecific pollinations resulted in a comparable percentage of germinating seedlings, the seedlings from the interspecific crosses had less seed dormancy and were more vigorous than the intraspecific seedlings. These results indicate that the decline of the American bittersweet may be due in part to interspecific hybridizations with the invasive introduced species, and that the distinct genetic identity of C. scandens may be threatened.