If one bittersweet vine isn't enough for your garden, you can propagate it and grow more. You can either start growing bittersweet cuttings or plant bittersweet seeds. If you are interested in propagating American bittersweet vines, click here for tips.
Oriental Bittersweet is an invasive climbing vine from Asia that can kill trees reducing our bio-diversity. The Oriental Bittersweet vine will climb other plants, wrapping itself like twine. Since this is a somewhat rigid woody vine that grips tightly, as the diameter of the tree increases it will crush and girdle itself against the vine.