Gardening Articles: Landscaping :: Trees, Shrubs, & Vines
by Alain Charest
Trumpet vine (Campsis radicans) is a true North American plant. Native to the Southeast, it grows in most areas of the continent and is able to take the cold and the heat in stride. But it's northern gardeners like me that appreciate it most: Few hardy vines can offer an equal amount of color and vigor. Many garden plants are described as blooming all summer long, but trumpet vine is one of the few to actually live up to this description. Its only requirements are a sunny exposure and a good pruning in winter.
I became acquainted with trumpet vine when I first bought a house and got serious about gardening. It was August when I moved in, and the garage wall was covered with hundreds of large trumpet-shaped orange blooms that attracted hummingbirds. It took me some time to find out what the spectacular plant was. Trumpet vine is very woody and at first I was under the impression it was a tree that had grown right against the wall. A closer inspection revealed adhesive suckers and eventually I found it identified among climbing plants.
The next spring, I was worried when the plant didn't show any sign of life. I had been looking forward to a repeat of the "wall of blooms" from the previous summer, but the plant looked just about dead. Then, late in spring, it started showing a few green sprouts. I then realized that trumpet vine, even if it could easily put up with my USDA Zone 5 Canadian winter, likes heat and would wait for it before coming out of its long winter sleep. Nonetheless, it will survive areas as cold as zone 4, although in this zone it may suffer winter damage. While it is very adaptable, it has not become a problem plant and it does not tend to invade areas where it is not native.
Types of Trumpet Vines
Our North American native species, Campsis radicans, produces large, 3-inch-long, trumpet-shaped orange flowers at the tip of each year's new growth. 'Flava' and 'Aurea' are yellow varieties of the same plant. In my experience, neither is as hardy as the species. Each leaf is divided into as many as 11 leaflets, each 2 to 3 inches long.
Campsis grandiflora (aka Bignonia chinensis) is a Sino-Japanese species, which can be grown in mild climates. It won't survive long periods of frost. This trumpet vine is very similar to C. radicans but blooms in late summer and fall. The variety 'Thumbergii' has shorter but wider flowers. This plant is hardy to zones 7 through 9.
The two species, C. radicans and C. grandiflora, have been crossed to produce Campsis tagliabuana, which produces large attractive salmon-red blooms. Like its Chinese ancestor, it is more cold sensitive than the native, but by most standards is still reasonably hardy, to zone 7. It is also very tolerant of alkaline soil. Common varieties include 'Crimson Trumpet' and 'Mme. Galen' (salmon-red flower).