Ornamental · Convolvulaceae
Cardinal Climber
Ipomoea × multifida
Hand it full sun and lean soil, and this fast vine throws out scarlet trumpets that hummingbirds chase all summer long.
Full sun
Every 3–7 days
50–95°F · 10–35°C
60–75 days
Overview
Cardinal climber is a fast twining annual that'll blanket a trellis or fence in just one season. It's part of the morning-glory family and comes from crossing cypress vine with red morning glory, which is where it gets its deeply cut, palmate green leaves and those small, bright red trumpet flowers. Hummingbirds can't seem to leave them alone.
This vine climbs hard and can reach 6 to 15 feet (1.8 to 4.5 m) over a warm summer, so it needs something to grab onto right from the start. It only acts like a perennial in the warmest zones, and pretty much everywhere else you'll grow it as an annual, sowing fresh each spring once the frost has cleared.
It doesn't ask for much at all. Full sun and ordinary, well-drained soil will do, and too much fussing actually works against you, handing you leaves instead of flowers. The one thing to keep an eye on? Its habit of self-seeding, which can leave you with volunteers the next year.
Care
The short version: full sun, average to lean well-drained soil, and roughly an inch of water a week. Skip the fertilizer, give it something to climb, and pull the green seed pods if you'd rather it didn't spread.
Light
Give cardinal climber full sun and you'll get the best show of flowers. It'll still grow in partial sun or light shade, but every hour of shade swaps blooms for more leaf, so a bright, open spot really pays off.
Water
Aim for about 1 inch of water a week and keep the soil evenly moist while the vine is finding its feet. It can shrug off short dry spells once it's settled in, but steady moisture is what gives you the most flowers.
Soil
Plant it in average to lean, well-drained loam or sandy soil, anywhere from pH 6.0 to 8.0. Rich ground actually works against you here, pushing lots of vine and few flowers, so go easy on the compost.
Temperature
This is a warm-weather vine that's happy between 50°F and 95°F (10°C to 35°C). It needs warm soil to get going and frost finishes it off, so there's really no reason to set it out early.
Humidity
Ordinary outdoor air suits it just fine, so you don't have a humidity number to hit. Good airflow is what counts, keeping that dense foliage from turning into a pest hideout.
Feeding
It barely needs feeding at all. Skip the fertilizer in decent soil, and in really poor ground use only a light balanced feed, since high nitrogen leaves you with leaves instead of flowers.
Pruning
Pinch the young tips to make the vine branch out fuller, and train or trim it onto its support as it climbs. Snip off the green seed pods if you'd like to keep it from self-seeding.
Repotting
Grown as an annual, it lives a single season and won't be carried over, so there's no repotting in the usual sense. In a container, start fresh each spring with new soil rather than reusing a rootbound pot.
Size & spacing
Expect a vine that climbs 6 to 15 feet (1.8 to 4.5 m) tall but stays just 6 to 12 inches (15 to 30 cm) wide. Give it a tall, sturdy support and a bit of breathing room so air can move through the foliage.
When to plant
Cardinal climber loves warmth and won't put up with frost. Start your seeds indoors a few weeks before the last frost, move the plants outside once the soil's warmed up, and you'll get blooms from summer straight through to the first frost.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: 4-6 weeks before last frost; nick and soak hard seeds first
- Plant: After last frost when soil is warm
- Harvest: Summer to frost
Hardiness
USDA hardiness zones: 10–12
Temperature: down to -1°C
Troubleshooting
Cardinal climber doesn't cause much grief, and when something does go sideways it usually turns up in the flowers, the leaves, or as stray seedlings. Catch the early signs and you can sort it out before it spreads or sulks. Find what matches below, then take action.
Speckled, chewed leaves with a sticky coating
A few bugs like this vine: sap-suckers like aphids and spider mites, plus chewers like Japanese beetles and leaf miners. Flip the leaves over and look at the new growth to spot which one you've got, then blast them off with a strong jet of water or reach for insecticidal soap or horticultural oil. You'll want to hand-pick beetles and tear off any mined or really chewed-up leaves.
Fix:
- Spray off aphids and mites with a strong jet of water
- Apply insecticidal soap or horticultural oil
- Hand-pick Japanese beetles
- Remove and destroy mined or heavily infested leaves
Lots of leaf, barely any blooms
When the soil's too rich or the spot's too shady, this vine just keeps making leaves instead of flowers. Most of the time too much nitrogen is behind it, so cut the feeding and get the vine into full sun. Lean, well-drained ground plus bright light is what brings those red trumpets back.
Fix:
- Stop high-nitrogen feeding
- Move or train the vine into full sun
- Grow in leaner, well-drained soil
Surprise seedlings showing up next year
Here's the thing: this vine self-seeds freely, especially where it's warm, so dropped seed sprouts right where the plant grew last time. Just pull the volunteers you don't want. Want a longer-term fix? Clip off the green seed pods before they ripen and scatter.
Fix:
- Pull unwanted seedlings
- Remove developing seed pods before they mature and drop
Toxicity
This one's toxic, and the danger is packed into the seeds. They carry indole alkaloids of the LSA type that can bring on stomach upset and, in bigger amounts, agitation and hallucinogenic effects in pets, livestock, and people. The foliage is a milder concern, but keep the seeds and seed pods well clear of animals and kids.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Mild
If a cat nibbles a leaf or two, you'll usually just see an upset stomach and some vomiting. The seeds are where the real trouble is, and a mouthful can leave a cat agitated, trembling, and disoriented.
Dogs Mild
Chewed leaves tend to bring on drooling and a round of vomiting. But if a dog gets into the seeds, you can expect it to turn restless, shaky, and plainly off.
Horses Mild
It's listed as toxic to horses too, and the seeds are what carry the alkaloids that upset the gut and, in enough quantity, the nervous system. Keep grazing horses away from the vine and its seed pods.
Rabbits Caution
Those same seed alkaloids that bother cats and dogs would hit a small grazer hard, so treat this vine as off-limits for rabbits rather than safe browse.
Livestock Caution
Goats, sheep, and cattle can take in the LSA-type alkaloids if they graze the seeds or seed pods, and that risks both stomach and nervous-system trouble. Fence it off from pasture.
Birds Caution
The hazard sits in the seeds, so don't let poultry or pet birds peck at the pods, even though the foliage is less of a worry.
People Caution
No part of this vine is meant to be eaten. The seeds hold indole alkaloids that can cause stomach upset and hallucinogenic effects, so keep them well out of reach of children.
Keep seeds and seed pods away from pets and children; the seeds are the hazardous part.
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
Since cardinal climber is a hybrid, the names worth knowing are its two parents. You'll spot both in gardens, and they explain where this vine gets its looks.
Ipomoea quamoclit (cypress vine)
It's one parent of the hybrid, and you'll know it by the very fine, thread-like leaves cut into needle-thin segments that look more fern-like than the cardinal climber's own foliage.
Ipomoea coccinea (red morning glory)
This is the other parent, a red-flowered morning glory whose broad, heart-shaped leaves stay whole instead of being finely cut.
How to propagate
Cardinal climber grows easily from seed, and seed is really the only way you'll start it. The one trick? Getting past that tough seed coat.
SeedEasy
Start indoors 4-6 weeks before last frost or sow outdoors after frost in warm soil · 5-10 days to germinate; weeks to begin climbing
You'll grow cardinal climber from seed, starting it indoors 4 to 6 weeks before your last frost or sowing outside once the soil's warmed up. The seed coat is hard, so nick it and soak the seeds overnight before sowing if you want even germination. Seedlings break ground in 5 to 10 days and then take a few more weeks before they really start to climb.
Myths
Cardinal climber, cypress vine, and cardinal flower are all the same plant.
Not quite. Cardinal climber is a hybrid of cypress vine and red morning glory, and its deeply lobed, palmate leaves land somewhere between its two parents in shape. Cypress vine has finer thread-like foliage, while red morning glory has broad heart-shaped leaves. And cardinal flower (Lobelia cardinalis) is a completely different plant, an unrelated perennial in another family, not a climbing annual vine at all.