Campsis radicans aka Trumpet Creeper

Trumpet vine, or trumpet creeper, is Campsis radicans, a member of the Bignoniaceae family. It grows wild across the central and eastern United States, from Pennsylvania and Missouri south to Florida and Texas. It also reaches a small part of northern Mexico. The plant has escaped from gardens and spread into many northern states. In the wild it turns up in woods, thickets, swamps, fields and along roadsides. Some people call it cow-itch vine.

This is a deciduous, woody vine with many stems and very strong growth. It clings to walls, fences and trees with short aerial rootlets. With support it climbs 30 to 40 feet (9 to 12 m). Spread on a structure is often 8 to 13 feet (2.5 to 4 m). Without support it sprawls across the ground. Older stems carry pale tan bark that peels slightly. The leaves are opposite and odd-pinnate, up to 15 inches (38 cm) long. Each leaf holds 7 to 11 toothed leaflets, glossy dark green on top. Fall color is weak, usually a dull yellow-green.

Clusters of trumpet-shaped flowers open on new growth from midsummer into early autumn. Each flower is about 2.5 to 3 inches (6 to 8 cm) long. Colors range from orange to scarlet, and some selections bloom yellow. Hummingbirds are the main pollinators, and butterflies visit too. After bloom come long, bean-like capsules 3 to 5 inches (8 to 13 cm) long. They ripen from green to brown and split open. The flat, two-winged seeds then drift away on the wind.

Trumpet vine is easy to grow in almost any soil that does not stay waterlogged. Clay, sand, loam and chalk all suit it, whether acid or slightly alkaline. It flowers best in full sun and blooms poorly in heavy shade. Once established it copes well with drought, heat and deer. It suits USDA zones 4 to 9. Cold winters in zone 4 can kill back some twigs. In the UK it rates H4 and does best against a warm, sunny wall. Since flowers form on new wood, pruning in late winter or early spring costs no bloom.

Gardeners use it to cover fences, arbors, trellises and walls fast. It can also hide rock piles or old stumps. The vine fits wildlife, native and hummingbird gardens. It also hosts the caterpillars of the plebeian sphinx moth.

The main problem is its vigor. The plant sends up suckers from underground runners and seeds itself freely. It can form dense thickets that smother nearby plants. Connecticut lists it as showing invasive tendencies. Mature vines grow heavy and need a sturdy support. The woody stems can force their way under wooden siding. Serious pests and diseases are rare. Aphids, planthoppers, leaf spot, powdery mildew and honey fungus may appear now and then. The plant is also highly flammable.

The plant has no known food uses. Eating the flowers causes only mild poisoning. Handling the leaves or sap can bring brief redness, itching or swelling of the skin.