Shrub · Bignoniaceae
Trumpet Vine
Campsis radicans
Give it full sun and a sturdy support, and the trumpet vine draws hummingbirds all summer.
Full sun
Every 7–14 days
730–1095 days
USDA 4–9
Overview
Trumpet vine is a fast, woody climber from the eastern United States, grown for the show of orange-red trumpets that pull in hummingbirds from midsummer into fall. It clings by aerial rootlets and can run up 25 to 40 feet (7.5 to 12 m), scaling arbors, fences, and walls with ease. Hardy from zones 4 to 9, it shrugs off cold, heat, drought, and poor ground alike.
The catch is its vigor. Left alone, it spreads by underground suckers and self-sown seed into dense colonies, and its weight and clinging roots can damage the very structures it climbs. This is a plant for a spot where you can let it run or stay on top of it, not a delicate climber for the side of the house.
Grow it on a heavy, freestanding support, plant it in lean soil, and prune it hard each year, and you get the flowers without the regrets. The folk name cow itch vine is a fair warning too, since the sap can irritate skin, so keep your gloves on when you work with it.
Care
The short version: full sun, lean soil, and a very sturdy support. Water young plants until they take hold, then leave them be, skip the fertilizer, and prune hard in late winter to keep it in bounds.
Light
Trumpet vine flowers best in full sun, six or more hours a day. It will grow in partial sun or light shade, but shade trades blooms for leaves, leaving you a rampant green vine with little color.
Water
Water young plants while they establish, then step back. Once settled, it's drought tolerant and gets by on rainfall in dry to moist soils, so an established vine rarely needs a drink from you.
Soil
It takes clay, sand, loam, or poor ground and a wide pH range from 5.5 to 8.0. Lean soil is actually the goal here, since rich ground only feeds its vigor and cuts the flowering, while it handles dry to occasionally wet spells without complaint.
Temperature
Cold-hardy and heat-proof, it survives from about -29°F to 100°F (-34°C to 38°C), which covers zones 4 through 9. Few climbers take a harsh winter and a baking summer in such stride.
Humidity
Ordinary outdoor air suits it, so there's no humidity target to hit. It grows across a broad range of climates without any fuss over moisture in the air.
Feeding
Skip the fertilizer. Rich soil and heavy feeding only push more leaf and fewer flowers, so the plant does better hungry, and lean ground keeps its already-aggressive growth in check.
Pruning
Prune hard in late winter or early spring to control size and shape. It blooms on new growth, so cutting back never costs you flowers, and yearly thinning of the woody stems plus removing root suckers is what keeps it off your structures.
Repotting
This is a ground-grown vine, not a houseplant, so repotting rarely comes up. In the uncommon case it's containerized, look for roots filling the pot and suckers pushing out the drainage holes.
Size & spacing
Expect a big climber, running 25 to 40 feet (7.5 to 12 m) tall and spreading 5 to 10 feet (1.5 to 3 m) wide. Give it real room and a strong structure, and keep it well clear of anything you'd rather it didn't swallow.
When to plant
Trumpet vine is tough and in no hurry. Set plants out in spring after the frost, or in fall in mild zones, and prune hard in late winter before growth starts. The orange trumpets follow through summer, from June into September, on the new wood.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Late winter to early spring; seed needs cold stratification, though the plant is usually propagated from root cuttings or suckers rather than seed.
- Plant: Spring after frost, or fall in mild zones
- Harvest: Summer (June to September)
Hardiness
USDA hardiness zones: 4–9
Temperature: down to -34°C
Troubleshooting
Most trumpet vine trouble comes from its sheer vigor rather than pests or disease. The vine spreads where you don't want it, leans on whatever it climbs, and sometimes grows all leaf and no flower. Match what you see below, then rein it in before it gets ahead of you.
Siding, mortar, and gutters damaged by the clinging vine
The trumpet vine grips with clinging aerial rootlets that work into mortar, wood, and any small crack, and a mature plant carries enough woody weight to crush a fence or weak trellis. Pulled off a wall, it takes the surface with it. Grow it only on a heavy freestanding support such as a metal arbor or masonry, never on the house, and prune it back hard each year to hold down the weight.
Fix:
- Grow only on a very sturdy freestanding support such as a heavy metal arbor or masonry, not on house walls or wooden structures
- Keep the vine off buildings, gutters, and weak fences by pruning back hard
- Avoid clinging vines on wood, which can be damaged or rot from trapped moisture
New shoots popping up far from where you planted it
This is aggressive suckering, the trumpet vine's defining habit. It sends out underground runners and drops bean-like seed capsules, so new shoots and seedlings surface yards from the parent and can choke out everything around them. Dig or pull the suckers the moment they appear, mow any that reach the lawn, and cut off the seed pods before they split.
Fix:
- Dig or pull root suckers as soon as they appear, removing as much root as possible
- Mow suckers repeatedly where the plant adjoins lawn to exhaust them
- Remove spent flowers and seed capsules before they split to limit self-seeding
- Site it near concrete or mowable areas to make suckers easier to control
Lush leafy vine that refuses to flower
A trumpet vine that grows like mad but won't bloom is usually too young, too shaded, or too well fed. Young plants can take a few years to settle in before they flower, and shade or rich, nitrogen-heavy soil pushes leaves at the expense of blooms. Move it into full sun, hold off on fertilizer, and give it time, since flowering improves as the plant matures.
Fix:
- Site or relocate in full sun (6 or more hours)
- Be patient; allow the plant to mature, as blooming improves with age
- Avoid nitrogen-rich fertilizer and grow in leaner soil
- Root-prune or restrict the roots slightly to encourage flowering
Toxicity
Trumpet vine isn't a serious poison, but it isn't harmless either. The bigger hazard is to people, since the leaves, flowers, and sap can bring on contact dermatitis, the skin rash that earned it the name cow itch vine. Pets that chew it tend to get only mild irritation, so wear gloves when you handle the plant and keep curious animals from gnawing it.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · People
Safe for
Birds
Cats Mild
A cat that chews the leaves or flowers may drool a little or have a brief upset stomach, and the sap can leave its mouth or skin irritated. Serious poisoning isn't a concern here.
Dogs Mild
Chewing the foliage tends to cause nothing worse than some drooling and a passing bout of mild stomach upset, with possible mouth or skin irritation from the sap.
Horses Mild
A horse that nibbles the vine may show light mouth or skin irritation and a touch of digestive upset, but it isn't a dangerous plant for them.
Rabbits Caution
There's little record of how rabbits react, so keep them away from it as a precaution rather than offer it as forage.
Livestock Caution
Grazing animals generally leave it alone, and any irritation from chewing it stays mild, but it's best treated as something to fence off rather than graze.
People Caution
Handling the leaves, flowers, or sap can bring on contact dermatitis, with skin redness, itching, and blistering, along with eye irritation. The old name cow itch vine says it plainly, so wear gloves and long sleeves whenever you prune it.
Birds Safe
The vine poses no eating hazard to birds, which visit the flowers for nectar more than they bother the foliage. Hummingbirds in particular flock to the blooms.
Not internally poisonous to pets, but the leaves, flowers, and sap can cause contact dermatitis with skin redness, itching, and eye irritation in sensitive people who handle the plant (hence the folk name cow itch vine). Wear gloves and long sleeves when pruning or handling.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
A few named forms and a close Asian cousin give you some choice in color and restraint. These are the ones worth knowing.
'Flava' (Yellow Trumpet, f. flava)
This form trades the usual orange-red for clear yellow to orange-yellow trumpets.
'Madame Galen' (Campsis × tagliabuana)
A cross between C. radicans and C. grandiflora, it carries cantaloupe-orange to salmon-red flowers and still suckers and self-seeds, though it runs a little less wild than the straight species.
Campsis grandiflora (Chinese trumpet creeper)
The Asian species bears large orange-and-yellow flowers, climbs far less aggressively with fewer aerial rootlets, and needs added support to hold itself up.
How to propagate
Trumpet vine multiplies almost too easily, by cuttings, division, seed, or simply where a stem touches the ground. Most gardeners are trying to slow it down rather than make more.
Stem cuttingsEasy
Summer (softwood) cuttings · 4 to 8 weeks to root
Softwood cuttings taken in summer root with little fuss, striking in about 4 to 8 weeks. It's one of the simplest plants to start this way.
DivisionEasy
Dormant season or early spring · One season
The vine throws up rooted suckers all on its own, so the easiest increase is to dig one in the dormant season or early spring and replant it. A divided sucker settles in within a single season.
SeedModerate
Spring after cold stratification · Several years to first bloom
Seed from the bean-like capsules sprouts readily once it has had a cold spell, sown in spring after stratification. Be patient, though, because seedlings can take several years to reach their first bloom.
LayeringEasy
Spring to summer · One season
Where a stem rests on the soil from spring through summer, the aerial rootlets and nodes take hold and root on their own. A layered stem is ready to separate within a season.
Myths
Trumpet vine is poisonous and will seriously harm dogs or cats that chew it.
Campsis radicans isn't on ASPCA toxic-plant lists, and reported toxicity from eating it stays low, so a pet that chews it usually faces nothing worse than a little drooling or mild stomach upset. The real hazard is contact dermatitis, a skin and eye irritation in people who handle the foliage or sap, not internal poisoning.
It is a tidy, well-behaved climber for the side of a house.
It is anything but tidy. It spreads by root suckers and self-seeding into dense colonies, and its clinging aerial roots and heavy woody growth can wreck siding, mortar, wood, gutters, and weak supports. Give it a very sturdy independent support and prune it hard every year, never the wall of your house.