About Campsis radicans (L.) Bureau
Campsis radicans, commonly known as trumpet vine, is a climbing or trailing vine that can reach lengths of up to 10 metres, or up to 12 metres for its climbing stems. Rigid, woody arching secondary vines up to 2 metres long extend outward from the main stem. This species can form dense groundcover, or grow as an aggressive liana that overgrows other plants and buildings. It climbs using aerial rootlets and twining stems. Its bark is tan and shreds easily. Leaves are opposite and odd-pinnately compound, meaning they have an odd number of leaflets with one terminal leaflet. The entire leaf can grow up to 18 centimetres long, holding 7 to 13 leaflets. Each leaflet measures roughly 8 centimetres long and 4 centimetres wide. New leaflets are emerald green, maturing to a shiny dark green. Leaflets are shaped ovate to broadly lanceolate with coarsely serrate edges. Campsis radicans is native to the eastern United States and extreme southern Ontario, Canada. It has become naturalized in parts of the western United States, additional areas of Ontario and southern Quebec, parts of Europe, and scattered locations across Latin America. In pre-Columbian North American landscapes, this species was mostly restricted to swamp bottomlands. It has since successfully colonized thickets, fencerows, abandoned farmland, floodplain forests and their edges, and river banks. Its flowers bloom for around three months over summer, and are very attractive to hummingbirds including the ruby-throated hummingbird. Many bird species nest in its dense foliage. Halictid bees, flies, and ants feed on nectar from the plant's extra-floral nectaries. Orchard orioles (Icterus spurius) have been observed engaging in nectar robbing: they puncture and enlarge holes at the base of flowers to access nectar. Certain sphinx moths with elongated proboscises can successfully feed on trumpet vine nectar while hovering in front of flowers. After flowering, the plant produces large seed pods. As pods mature, they dry and split open to release hundreds of thin, brown, paper-like seeds. These seeds germinate easily when stratified. Larvae of Clydonopteron sacculana, the trumpet vine moth, feed on the plant's seed pods. Campsis radicans occasionally serves as a food source for large mammals. This species is slightly toxic if ingested. Contact with its flowers and leaves can cause swelling, skin redness, and contact dermatitis. It is often considered a weedy species, and its aggressive spread can be controlled by thinning vines during the growing season and cutting them back in winter. In cultivation, trumpet vine grows very vigorously. In warm weather, it produces aerial rootlets that cling to any available surface, which eventually develop into heavy woody stems several centimeters in diameter. It grows well on arbors, fences, telephone poles, and trees, though its vigorous growth can damage these structures over time, so ruthless pruning is recommended. Outside its native range, this species has the potential to become invasive, even as far north as New England. It also grows well across much of southern Canada, but produces fewer flowers when it does not get extended summer heat. Several cultivated varieties exist: the larger-flowered hybrid 'Mme Galen' was introduced around 1889 by the Tagliabue nurserymen of Lainate near Milan, Italy; the yellow-flowered form Campsis radicans f. flava has earned the Royal Horticultural Society's Award of Garden Merit; and the deeper red cultivar 'Flamenco' is available to gardeners.
