What Time is it in Nature: Woolly Pipevine

North Carolina has a variety of native flowering vine species that grow up trees in forested areas. One species, the Woolly Pipevine (Aristolochia tomentosa), is both interesting to look at and is an important food source for a popular insect.

Woolly Pipevine is a tall, climbing, woody vine native to most of the eastern US. Though it needs support to gain much height, the vines can easily reach 30 feet tall if well supported by a tree (or a trellis in a landscaped environment) as it grows up the trunk. It has big, heart-shaped leaves that can reach 10 inches long and are deep green on top and paler green underneath. Both the common name, Woolly Pipevine, and the species name, tomentosa, refer to the surface of the leaves, stems, and flowers as they are covered in dense, short hairs.

The “pipevine” in the common name Woolly Pipevine comes from the interesting flower:

The flowers resemble the pipes smoked by the Dutch and northern Germans in the past, with a sort of widened bowl sitting at the tip of a longer curved tube. The flowers bloom from May into June and reach lengths of just under two inches long, though you might not see the flowers in spite of their size as they tend to grow back behind the leaves and are subtly colored. They have an interesting form of pollination. When a fly or bee follows the sweet smell to the flower and crawls inside to gather nectar, they rub against the stamens that line the inner flower and are dusted with pollen. The tube of the flower is also lined with hairs. These hairs allow the pollinator to crawl into the flower, but then traps it inside. As the pollinator struggles to get out, it is covered in pollen. Eventually, the hairs wither and the insect can crawl back out of the flower, but it may spend a few days inside the flower before being released.

Woolly Pipevine and other Aristolochia species contain a toxin called aristolochic acid, a highly carcinogenic substance as well as a potent kidney toxin. In spite of its considerable toxicity, medicines made from pipevine plants have been used in many different cultures. The name Aristolochia in fact refers to an ancient use in childbirth (aristos = best and locheia = childbirth) and some pipevines are still used in Chinese medicine for arthritis and edema. There is little scientific evidence that these “medicines” do more good than harm, however, and several recent studies have linked ingestion of pipevine to a variety of cancers and kidney failure. It is definitely best to avoid consuming pipevine!

While Woolly Pipevine might be toxic to people and has very few pest species associated with it due to its toxicity, it is a very important food source for Pipevine Swallowtail Butterflies. These butterflies lay their eggs on the leaves and the larvae feed on the leaves as they grow. The caterpillars store the toxins internally to protect themselves against predators, using the aristolochic acid as a weapon against other animals that might want to eat them. You’ll often see small clusters of bright red eggs and reddish or deep purple caterpillars on the leaves and adult Pipevine Swallowtails fluttering around the vines.

We have a healthy Woolly Pipevine plant growing in the Prairie Ridge Nature Neighborhood Garden! On your next visit, head into the main garden entrance under the roof garden and turn right to see the big, fuzzy green leaves covering the fence. Take a close look. You just might see a group of Pipevine Swallowtail eggs or caterpillars lurking underneath a leaf of this fascinating plant!

What Time is it in Nature is a weekly feature highlighting the current plants, animals, and other wildlife at the Musuem’s public outdoor facility, Prairie Ridge Ecostation. Find out more about the natural happenings at Prairie Ridge at our What Time is it in Nature Archive!

Photos by Chris Goforth