Shrub · Bignoniaceae
Trumpet Vine
Campsis radicans
Hand it full sun and something sturdy to climb, and the trumpet vine will pull in hummingbirds all summer long.
Full sun
Every 7–14 days
730–1095 days
USDA 4–9
Overview
So what is a trumpet vine? It's a fast, woody climber from the eastern United States, and people grow it for those orange-red trumpets that hummingbirds can't resist from midsummer into fall. It grabs on with little aerial roots and can shoot up 25 to 40 feet (7.5 to 12 m) over an arbor, fence, or wall. It's hardy in zones 4 to 9, too, so cold, heat, drought, and rough soil don't really faze it.
Here's the catch, though: it grows like it means it. Leave it be and it'll travel by root suckers and dropped seed into thick patches, and all that weight and those grippy roots can start to hurt whatever it's climbing. So it's really a plant for a spot where it can run loose or where someone's happy to keep after it, not a dainty thing for the side of the house.
The good news? Keeping it happy isn't complicated. Put it on a heavy support that stands on its own, grow it in lean soil, and cut it back hard once a year, and you'll get the flowers without the headaches. Oh, and that nickname cow itch vine is no joke, since the sap can bug your skin, so it's worth keeping gloves on while you work.
Care
The short version: full sun, lean soil, and a really sturdy support. Water young plants till they settle in, then pretty much leave them alone, hold off on fertilizer, and prune hard in late winter so it doesn't take over.
Light
It flowers best in full sun, so aim for six or more hours a day. Sure, it'll grow in partial sun or a little shade, but shade means way more leaves and hardly any flowers, and who wants a giant green vine with no color?
Water
Give young plants a steady drink while they're getting established, and after that you can pretty much back off. Once it's settled it's drought tolerant and gets by on rain in dry to moist soil, so a grown vine won't ask you for much.
Soil
It's not fussy about soil at all: clay, sand, loam, poor ground, whatever, and a pH anywhere from 5.5 to 8.0 works. Funny enough, lean soil is what you actually want, because rich ground just pumps up its growth and cuts the flowers, and it handles dry to occasionally wet spells just fine.
Temperature
This one's tough. It comes through from about -29°F to 100°F (-34°C to 38°C), which is exactly why it's happy across zones 4 through 9. Not many climbers take a nasty winter and a scorching summer this well, right?
Humidity
No need to think about humidity here. Regular outdoor air is all it wants, and it grows across all kinds of climates without caring one bit about moisture in the air.
Feeding
You can just skip the fertilizer. Feeding it only gets you more leaves and fewer flowers, so it's actually better off a little hungry, and lean soil helps keep its already-pushy growth in check.
Pruning
Go ahead and prune it hard in late winter or early spring, don't hold back. It blooms on new growth, so cutting it never costs you flowers, and thinning the woody stems and pulling root suckers each year is really what keeps it off your stuff.
Repotting
This is an in-the-ground vine, not a houseplant, so repotting basically never comes up. If yours does happen to live in a pot, keep an eye out for roots filling the pot and suckers poking out the drainage holes.
Size & spacing
Just know it gets big: around 25 to 40 feet (7.5 to 12 m) tall and 5 to 10 feet (1.5 to 3 m) wide. Give it plenty of room and a strong structure, and keep it well away from anything you don't want it climbing all over.
When to plant
There's no need to hurry with this one. Pop plants in the ground in spring once frost's out of the way, or in fall if winters stay mild where you are, and cut it back hard in late winter before it starts moving. Then the orange trumpets show up all summer, from June into September, on the fresh growth.
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 of what goes sideways with a trumpet vine comes down to how fast it grows, not bugs or disease. It'll wander off where you didn't want it, lean its weight on whatever holds it up, and every so often grow nothing but leaves. Spot your issue below, then step in before it runs away from you.
Siding, mortar, and gutters getting torn up
The trouble is those clinging aerial rootlets, which work their way into mortar, wood, and any little crack, plus a mature plant is heavy enough to snap a fence or a weak trellis. Pull it off a wall and, yikes, the wall comes too. So keep it on a heavy freestanding support like a metal arbor or masonry, never the house, and prune it back hard every year to keep the weight down.
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 turning up nowhere near where it's planted
What's going on is aggressive suckering, and it's just what this vine does. Underground runners head off in every direction and those bean-like pods scatter seed, so you get shoots and seedlings popping up way past the parent, sometimes crowding out whatever's nearby. Dig or pull the suckers the second you see them, mow any that hit the lawn, and clip the seed pods off before they burst.
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
Loads of leaves but where are the flowers?
A trumpet vine that's growing like crazy but won't flower is usually too young, too shaded, or too well fed. Young plants can take a few years to get going, and shade or rich, nitrogen-heavy soil just pushes leaves instead of blooms. Move it into full sun, quit feeding it, and give it time, because it flowers more and more as it gets older.
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
Is it dangerous? Not really, but it's not totally innocent either. The thing to watch is your own skin, since the leaves, flowers, and sap can set off the itchy rash that got it named cow itch vine. A pet that chews on it usually just gets a little irritated, so wear gloves when you handle it and don't let curious animals gnaw on it.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · People
Safe for
Birds
Cats Mild
If a cat chews a leaf or flower, it might drool a little or get a quick stomachache, and the sap can leave its mouth or skin irritated. Nothing serious, though, so no need to panic.
Dogs Mild
A dog that chews the foliage usually just drools some and has a brief upset stomach, maybe with a bit of mouth or skin irritation from the sap. That's about it.
Horses Mild
A horse that nibbles it might get mild mouth or skin irritation and a little tummy trouble, but it's really not a dangerous plant for them.
Rabbits Caution
There's hardly any info on how rabbits handle it, so it's safest to just keep them away from it instead of letting them snack on it.
Livestock Caution
Grazing animals mostly leave it alone, and if they do nibble, any irritation stays mild, but it's still better to fence it off than let them graze on it.
People Caution
Handling the leaves, flowers, or sap can bring on contact dermatitis, with skin redness, itching, and blistering, plus some eye irritation. The name cow itch vine kind of says it all, so throw on gloves and long sleeves before you prune.
Birds Safe
Birds have nothing to worry about here, and they're after the nectar way more than the leaves. Hummingbirds especially love the flowers.
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
Want a different color, or something a bit calmer? A few named forms and one close cousin from Asia give you some choices, and these are the ones worth a look.
'Flava' (Yellow Trumpet, f. flava)
This one skips the usual orange-red and goes for clear yellow to orange-yellow trumpets instead.
'Madame Galen' (Campsis × tagliabuana)
It's a cross of C. radicans and C. grandiflora with cantaloupe-orange to salmon-red flowers, and while it still suckers and self-seeds, it's a bit less wild than the plain species.
Campsis grandiflora (Chinese trumpet creeper)
This Asian one has big orange-and-yellow flowers, climbs way more gently with fewer aerial rootlets, and needs a little extra support to hold itself up.
How to propagate
If anything, this plant makes new plants way too easily, whether from cuttings, division, seed, or just a stem flopping onto the dirt. Honestly, most folks are trying to slow it down, not grow more of it.
Stem cuttingsEasy
Summer (softwood) cuttings · 4 to 8 weeks to root
Take softwood cuttings in summer and they'll root without much trouble, usually in about 4 to 8 weeks. It's honestly one of the easiest plants to start this way.
DivisionEasy
Dormant season or early spring · One season
Since the vine keeps throwing up its own rooted suckers, the easy move is to dig one in the dormant season or early spring and plant it somewhere else. A divided sucker gets going within a single season.
SeedModerate
Spring after cold stratification · Several years to first bloom
Seed from those bean-like pods sprouts fine once it's had a cold spell, so sow it in spring after stratifying. Just be patient, because seedlings can take several years before they bloom.
LayeringEasy
Spring to summer · One season
Let a stem rest on the ground from spring through summer and its rootlets and nodes will take hold on their own. After a season, that layered stem's ready to cut loose and move.
Myths
Trumpet vine is poisonous and will really hurt a dog or cat that chews it.
Not so. Campsis radicans isn't on the ASPCA toxic-plant lists, and eating it barely registers, so a pet that chews some usually just drools a bit or gets a mildly upset tummy. The real problem is contact dermatitis, an itchy skin and eye reaction in people who handle the leaves or sap, not any kind of poisoning from swallowing it.
It's a tidy, well-behaved climber for the side of a house.
Not even close. It spreads by root suckers and self-seeding into thick colonies, and its clinging roots and heavy growth can chew up siding, mortar, wood, gutters, and any weak support. Give it a strong support of its own and a hard prune every year, and please, keep it off the actual house.