Celastrus orbiculatus -- Oregon

Round leaf bittersweet (Celastrus orbiculatus), formerly known as Oriental bittersweet or Asian bittersweet, is a vigorous woody vine that has naturalized in various regions outside its native range in East Asia, particularly in temperate climates similar to its origin. In the United States, it has spread across the Northeast and the southern Appalachian Mountains. Its rapid growth, ability to girdle trees, and dense foliage contribute to the competition with native vegetation by smothering plants and altering forest dynamics. It reproduces both sexually, through prolific seed production, and vegetatively, via root sprouting. Birds and small mammals play a crucial role in long-distance seed dispersal, while some human activities may also contribute to its unintentional spread. Although not a direct health threat to humans or livestock, the vine can form impenetrable thickets that hinder movement and disrupt habitats. Due to its aggressive nature and ecological impact in similar climates, round leaf bittersweet has the potential to become an invasive concern in the Pacific Northwest.