Japanese peppervine is an East Asian vine with leaves divided into three to five leaflets. In the eastern United States, you are more likely to see its relative porcelain berry (Ampelopsis glandulosa) growing wild.
Porcelain berry has a single leaf blade that may be shallowly or deeply lobed. Japanese peppervine has three to five separate leaflets; look where they join the leaf stalk.
Why they get mixed upThey are related climbing vines with toothed leaves.