Climbing Hydrangea, Decumaria barbara, may often be mistaken for poison ivy, Toxicodendron radicans, from fall through winter because both deciduous vines have adventitious roots that make them look hairy. A key difference it that climbing hydrangea has opposite leaves while poison ivy has alternate leaves where this pattern translates to the branching patterns of stems and that includes branching of fruiting clusters and roots. But some people don’t care enough to worry about the difference similar to killing every snake they see even if it has round pupils rather than vertical cat like slit of our venomous snakes because every snake they see is a ‘copper-headed-rattle-moccasin’ and better off dead no mater how green it is. The excuse is the same for both snakes and hairy vines because those people are not even going to get close enough to see the difference although it is more likely that they just don’t want to pay that much attention, making me wonder if tracking them all would show a difference in the frequency, age of onset, and/or the progression rate of Alzheimer’s disease. The rest of the year the leaves on these two vines are obviously different where climbing hydrangea has simple leaves that look like they could be evergreen while poison ivy has the infamous trifoliolate leaves. Another key difference is the flower and fruit where those of climbing hydrangea are white terminal flowers and dry capsules while poison ivy has green axillary flowers that become creamy drupes. The white flowers of climbing hydrangea are often produced only after the vine reaches the top of what ever it climbs, but I have seen it tricked when the bark of a dead snag peeled off along with the attached top of the vine. It is important to know the binomial names because wood-vamp is another vernacular name for D. barbara, while an exotic plant in the nursery trade is also called climbing hydrangea.