A trumpet vine, or Campsis radicans for the formally inclined, is a flowering vine native to the Southeastern region of the United States. Contrary to the name, trumpet vines do not actually produce trumpets, in case you're wondering where trumpets come from, but they do put out a plethora of trumpet-shaped flowers in the spring and summer. Gardeners have a love it or hate it relationship with the trumpet vine, with some people loving this showy flowering plant, while others loathe it.
Trumpet vines are woody climbing vines with ovate leaves. The leaves start out a pale green, becoming darker over time, and the distinctive flowers may be red, orange, yellow, or cream, classically with pale throats. In the fall, the plant produces an array of hanging seed pods. Butterflies and birds cannot resist a trumpet vine in full flower, and trumpet vines also provide habitat for many bird and insect species in their densely interlaced branches and leaves.
Some gardeners struggle with trumpet vines because in the right climate, these plants can become out of control. In fact, some people classify them as invasive, because they grow very rapidly, and their sprawling tendrils can rip the siding off a house, destroy a fence, or promote rot in trellises, garden gates, and fenceposts. Once established, a trumpet vine is very difficult to eradicate, and gardeners should think carefully before planting a trumpet vine.
These vines grow in USDA zones four through 10, preferring full sun, loose fertile soil, and mild winters. In warm climates with good soil, a trumpet vine can run amok, but there are some ways to control a trumpet vine so that its ornamental nature can be enjoyed without becoming a hassle. One solution is to grow the plant in containers, restricting the spread of the roots and the size of the plant. Trumpet vines can also be aggressively pruned in the spring to inhibit new growth, and they should be grown on standalone trellises, rather than being trained to climb structures or fences, so that they cannot damage walls and fences.
Gardeners should be careful around trumpet vines because these plants have another hidden surprise in addition to being extremely vigorous: their milky sap causes contact dermatitis in some people. While not everyone will react to trumpet vine sap, some people develop itching, rashes, and hives just from brushing up against the leaves, let alone exposing themselves to sap from freshly cut branches.