Aristolochia clematitis

Cultivated as a medicinal plant since the Middle Ages, this 2-3' mounding and slowly spreading perennial hangs its small bright-yellow 'pipes' amidst large yellow-green heart-shaped leaves in early summer; poisonous; Aristolochia are larval plants for the pipevine swallowtail butterfly. S-PSh/M-D

Birthwort contains alkaloids that cause uterine contractions (the Druids version of RU422 but not nearly as safe, Don't eat it and don't picket us), curious pipe like flowers, weakly climbing vine, Europe. One of the high points of last summer was sitting around talking ferns with Dr. Storer, only to have him spot a 5th instar Papilio (Battus) philenor larva come crawling by, an event so unlikely that at first I thought it a joke. I've collected for years and never seen it in this part of Michigan; I figured Herb Wagner must have given him a larva or something. When I went to the garden to find it something to munch on there they were, 1.5" purple black, with magnificent fleshy tentacles like something out of the rainforest, devouring my Aristolochia clematis. We reared and released a couple dozen of the most incredible metallic blue green Pipevine swallowtails, they stayed around the nursery for weeks sipping from our mud puddles each morning but vanishing during the day. "If you grow it they will come," they sensed the only available food for miles and came here to lay eggs.