By RICK BORCHELT

If your gardening tastes run toward fast-growing vines that can engulf a small house in deep green in just one summer, trumpet creeper is for you. If you want a native plant that covers itself for months each summer with bright, showy, orange flowers, trumpet creeper is for you. If you want a hummingbird magnet for your yard, trumpet creeper is for you.

And if you want a plant with rich stories of robbery, protection rackets, poison, extreme engineering and chemistry — well, then, trumpet creeper is for you.

Trumpet creeper, Campsis radicans, is native throughout the eastern U.S. and into southern Canada. It’s found in every county in Maryland, sometimes to the chagrin of farmers, gardeners and utility workers. In keeping with the tropical origins of the trumpet vine family to which it belongs, the vigorous green vines grow best in broiling sunshine at the beach, along old fence lines, up telephone poles and in practically any sunny spot where it can latch onto a handy tree or structure to climb. 

Ants collecting sweet liquid from extrafloral nectaries on trumpet creeper buds

Technically, trumpet creeper is not simply a vine but a liana — a woody-stemmed vine rooted in the soil. Lianas are extremely common in moist, tropical forests, where they greedily climb trees to soak up sunlight above the jungle canopy. 

Trumpet creeper does its tropical liana counterparts one better: Its thick, ropy stems are covered with aerial rootlets that adhere to almost any surface. In my yard, those surfaces include deck rails, trees, fences, brick walls and window screens — and those are just the ones I’ve noticed. These rootlets put the “creep” in trumpet creeper, and lend it the species name of radicans, from a Latin root meaning “to take root” or “having rooting stems.”

But I forgive its aggressiveness — and trumpet creepers can grow 40 feet in a single summer and sprout with abandon wherever those rootlets touch ground again — for the spectacular floral display it offers from June through August. In early summer, it begins to grow stems that, instead of vining, arch away from the main trunk; they give trumpet creeper its genus name Campsis, from a Greek word meaning “bending” or “curving.” At the end of every pendulous branch, the liana sports clusters of fat tangerine buds that open into vivid orange trumpets that sway in the occasional summer breeze.

After flowering, trumpet creepers develop long, cigar-like pods filled with winged seeds.
Courtesy of Douglas Goldman

These blazing trumpets bring in droves of ruby-throated hummingbirds that are after the sweet nectar pooled in the bottom of the 6-inch trumpet. But the flower makes them work for their carbohydrate reward: It’s exquisitely engineered to ensure that a hummingbird has to do some pollination before it’s allowed to feed in the fiery throat of the trumpet.

The flower has a wide, flaring bell that narrows quickly into a constricted throat. Even a hummingbird’s long bill and tongue can’t probe deep enough to reach the nectar from the lip of the flower, so the bird has to grab onto the petals and push its head in until it bumps against the flower wall, where it narrows about a third of the way down the tube. From there, the bird can reach the nectar at the bottom with its bill and tongue. Deviously, the flower carries its reproductive organs, the stamens and pistil, right where the flower throat narrows, so when the hummingbird pokes its head in, it can’t help but brush pollen it’s picked up from the stamens of other trumpet creepers onto the sticky tip of the pistil, and at the same time pick up another load of pollen to carry to the next flower.

Trumpet creepers evolved alongside ruby-throated hummingbirds and can be pollinated by almost nothing else. Large bees like bumblebees can’t push past the constricting sphincter, and smaller ones are likely to get lost or drown in the deep well at the bottom of the flower. 

But nectar isn’t the only sweet reward that trumpet creepers offer. The flower exudes a sticky liquid from the tips of its buds, from the green collar around the base of the flower and at the base of the flower where it attaches to the stem. Scientists call these alternate honeypots extrafloral nectaries, and the sugar snack they produce attracts swarms of small bees and foraging ants. In return for the sugar, the stinging and biting diners protect the plant from herbivores that otherwise would snack on the buds and flowers. (To see ants clustering around trumpet creeper buds, go to tinyurl.com/2kac2f3a.) 

Robbers lurk in the lianas, too. Orchard orioles, Icterus spurius, bypass the tube entirely and stab the trumpet creeper flower directly at its base with sharp, pointed bills. These orioles, small brick-red and black cousins of the Baltimore oriole (Icterus galbula), favor the same brushy landscapes as trumpet creepers, and filched nectar can form a big part of their summer diet without any benefit to the plant.

Trumpet creepers were all the rage as garden plants in 19th-century Europe, as evidenced by this 1801 engraving by premiere French botanical artist Pierre Joseph Redoute.

Trumpet creeper goes by a number of other common names, as befits such a large, showy plant. Trumpet vine is one of them, as is hummingbird vine. One of the strangest common names is cow-itch, but chemistry explains why: The leaves contain a cocktail of toxins that causes contact dermatitis, similar to that produced by poison ivy, in some people.

Still, I’m sold on the aesthetic and wildlife value of trumpet creeper despite the need for constant vigilance and effort to keep it in bounds in my yard. For me, those bright orange trumpets play a fanfare of their own to herald the height of summer. 

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Rick Borchelt is a botanist and science writer who gardens and writes about natural history at his home in College Park. Reach him with questions about this column at rborchelt@gmail.com.