Ornamental · Convolvulaceae
Cardinal Climber
Ipomoea × multifida
Give it full sun and lean soil, and this fast vine throws scarlet trumpets that hummingbirds chase all summer.
Full sun
Every 3–7 days
50–95°F · 10–35°C
60–75 days
Overview
Cardinal climber is a fast twining annual vine that covers a trellis or fence in a single season. It belongs to the morning-glory family and comes from crossing cypress vine with red morning glory, which gives it deeply cut, palmate green leaves and small, bright red trumpet flowers. Hummingbirds find those blooms hard to resist.
The vine climbs hard and reaches 6 to 15 feet (1.8 to 4.5 m) in a warm summer, so it needs something to grab onto from the start. It runs as a perennial only in the warmest zones and is grown as an annual almost everywhere else, sown fresh each spring after the frost has passed.
It asks for very little. Full sun and ordinary, well-drained soil are enough, and too much pampering backfires by giving you leaves instead of flowers. The one habit to watch is its readiness to self-seed, which can hand you volunteers the following year.
Care
The short version: full sun, average to lean well-drained soil, and about an inch of water a week. Skip the fertilizer, give it a support to climb, and pull the green seed pods if you don't want it spreading.
Light
Give cardinal climber full sun for the best show of flowers. It will grow in partial sun or light shade, but every hour of shade trades blooms for more leaf, so a bright, open spot pays off.
Water
Aim for about 1 inch of water a week and keep the soil evenly moist while the vine is getting going. It shrugs off short dry spells once established, but steady moisture brings 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 works against you here, pushing lush vine and few flowers, so hold back on the compost.
Temperature
This is a warm-weather vine that runs between 50°F and 95°F (10°C to 35°C). It needs warm soil to get started and frost ends it, so there's no point setting it out early.
Humidity
Ordinary outdoor air suits it fine, so there's no humidity target to hit. Good airflow is the thing that matters, keeping the dense foliage from harboring pests.
Feeding
It barely needs feeding at all. Skip fertilizer in decent soil, and in very poor ground use only a light balanced feed, because high nitrogen gives you leaves instead of flowers.
Pruning
Pinch the young tips to make the vine branch fuller, and train or trim it onto its support as it climbs. Snip off the green seed pods if you want to stop it self-seeding.
Repotting
Grown as an annual, it lives one season and isn't carried over, so there's no repotting in the usual sense. In a container, start fresh each spring in new soil rather than reusing a rootbound pot.
Size & spacing
Expect a vine of 6 to 15 feet (1.8 to 4.5 m) tall but only 6 to 12 inches (15 to 30 cm) wide. Give it a tall, sturdy support and a little elbow room so air moves through the foliage.
When to plant
Cardinal climber needs warmth and won't tolerate frost. Start the seeds indoors a few weeks before your last frost, set the plants out once the soil has warmed, and the vine blooms from summer right up 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 rarely gives much trouble, and most of what goes wrong shows up in the flowers, the foliage, or as stray seedlings. Read the early signs and you can set it right before it spreads or sulks. Match what you see below, then act.
Stippled, chewed leaves with a sticky film
Sap-feeders like aphids and spider mites and chewers like Japanese beetles and leaf miners all go after this vine. Check the leaf undersides and new growth for the culprit, then knock pests off with a strong jet of water or treat with insecticidal soap or horticultural oil. Hand-pick beetles and strip out any mined or badly infested 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
Plenty of leafy vine but almost no flowers
Cardinal climber pours its energy into foliage when the soil is too rich or it sits in shade. Too much nitrogen is the usual culprit, so stop feeding and move or train the vine into full sun. Lean, well-drained ground and bright light bring the red trumpets back.
Fix:
- Stop high-nitrogen feeding
- Move or train the vine into full sun
- Grow in leaner, well-drained soil
Volunteer seedlings popping up the next year
This vine self-seeds freely, especially in warm climates, and dropped seed sprouts where the plant grew before. Pull the volunteers you don't want. The lasting fix is to snip 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 is a toxic plant, with the danger packed into the seeds. They hold indole alkaloids of the LSA type that can cause stomach upset and, in larger amounts, agitation and hallucinogenic effects in pets, livestock, and people. The foliage is a milder caution, but keep the seeds and seed pods well away from animals and children.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Mild
A cat that nibbles the foliage usually just gets an upset stomach and vomiting. The seeds are the real danger, and a mouthful can bring on agitation, tremors, and disorientation.
Dogs Mild
Chewed leaves tend to cause drooling and a bout of vomiting. Eat the seeds, though, and a dog can turn restless, shaky, and clearly out of sorts.
Horses Mild
The plant is listed as toxic to horses, with the seeds carrying the alkaloids that upset the gut and, in quantity, the nervous system. Keep grazing horses off the vine and its seed pods.
Rabbits Caution
The same seed alkaloids that trouble 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 pick up the LSA-type alkaloids if they graze the seeds or seed pods, which risks stomach and nervous-system trouble. Fence it away from pasture.
Birds Caution
The seeds hold the hazardous compounds, so keep poultry and pet birds from pecking the pods even though the foliage is a lesser worry.
People Caution
No part of this vine is grown to eat. The seeds carry indole alkaloids that can cause stomach upset and hallucinogenic effects, so keep them well away from 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
Cardinal climber is a hybrid, so the names worth knowing are its two parents. Both turn up in gardens and explain where this vine gets its looks.
Ipomoea quamoclit (cypress vine)
One parent of the hybrid, with very fine thread-like leaves split into needle-thin segments that look more fern-like than the cardinal climber's own foliage.
Ipomoea coccinea (red morning glory)
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 that is the only way it is started. The trick is getting past its 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
Grow cardinal climber from seed, starting indoors 4 to 6 weeks before your last frost or sowing outside once the soil has warmed. The seed coat is hard, so nick it and soak the seeds overnight before sowing to get even germination. Seedlings break ground in 5 to 10 days and take a few more weeks before they start to climb.
Myths
Cardinal climber, cypress vine, and cardinal flower are all the same plant.
Cardinal climber is a hybrid of cypress vine and red morning glory, with deeply lobed, palmate leaves that sit between its two parents in shape. Cypress vine carries finer thread-like foliage, while red morning glory has broad heart-shaped leaves. Cardinal flower (Lobelia cardinalis) is a different plant entirely, an unrelated perennial in another family rather than a climbing annual vine.