Ornamental · Convolvulaceae
Cardinal Climber
Ipomoea × multifida
Hand it full sun and lean soil, and this fast vine sends up scarlet trumpets that pull in hummingbirds all summer.
Full sun
Every 3–7 days
50–95°F · 10–35°C
60–75 days
Overview
Cardinal climber races up a trellis or fence in a single season, a fast twining annual that fills space in a hurry. A member of the morning-glory family, it comes from crossing cypress vine with red morning glory, a pairing that hands it deeply cut, palmate green leaves and small, bright red trumpet flowers. Hummingbirds zero in on those blooms.
Through a warm summer this vine pushes hard, climbing to 6 to 15 feet (1.8 to 4.5 m), so set it next to something it can grab from day one. Only the warmest zones keep it going as a perennial; nearly everywhere else gardeners grow it as an annual, sowing fresh seed each spring once frost has cleared.
Best of all, it asks for almost nothing. Full sun and ordinary, well-drained soil keep it happy, and fussing over it backfires by handing you leaves instead of flowers. Keep one eye on its eagerness to self-seed, which can leave you with volunteers the next year.
Care
The short version: full sun, average to lean well-drained soil, and about an inch of water a week. Hold off on fertilizer, hand it a support to scramble up, and snip the green seed pods if you'd rather it stay put.
Light
Hand cardinal climber full sun and it rewards you with the heaviest flush of flowers. Partial sun or light shade still grows the vine, but every hour of shade swaps blooms for extra leaf, so a bright, open spot earns its keep.
Water
Target about 1 inch of water a week and hold the soil evenly moist while the vine finds its feet. Once settled it brushes off short dry spells, yet steady moisture pulls out the most flowers.
Soil
Set it into average to lean, well-drained loam or sandy soil running anywhere from pH 6.0 to 8.0. Rich ground fights you here, fueling lush vine and stingy bloom, so go easy on the compost.
Temperature
This warm-weather vine thrives between 50°F and 95°F (10°C to 35°C). It demands warm soil to launch, and frost finishes it off, so setting it out early gains you nothing.
Humidity
Plain outdoor air keeps it content, so there's no humidity number to chase. What counts is good airflow, which stops the thick foliage from sheltering pests.
Feeding
It hardly wants feeding at all. Skip the fertilizer in decent soil, and in very poor ground reach only for a light balanced feed, since high nitrogen gives you leaves instead of flowers.
Pruning
Pinch the young tips to push the vine into fuller branching, and train or trim it onto its support as it climbs. Clip the green seed pods off if you want to shut down self-seeding.
Repotting
Run as an annual, it lives a single season and isn't carried over, so repotting in the usual sense never comes up. For a container, start fresh each spring in new soil instead of recycling a rootbound pot.
Size & spacing
Plan on a vine climbing 6 to 15 feet (1.8 to 4.5 m) tall while staying just 6 to 12 inches (15 to 30 cm) wide. Hand it a tall, sturdy support and a bit of breathing room so air slips through the foliage.
When to plant
Cardinal climber craves warmth and folds at the first frost. Get the seeds going indoors a few weeks before your last frost, move the plants outside once the soil warms, and the vine flowers 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 stays easygoing, and the few hiccups it hits land in the flowers, the foliage, or as stray seedlings. Catch the early signals and you can put it right before it sulks or spreads. Spot what matches below, then jump in.
Speckled, ragged leaves with a tacky coating
Plenty of pests target this vine: sap-suckers like aphids and spider mites plus chewers like Japanese beetles and leaf miners. Flip the leaves and scan the new growth to spot which one moved in, then blast the culprits off with a hard jet of water or reach for insecticidal soap or horticultural oil. Pick beetles off by hand and pull any mined or heavily hit 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
All vine, almost no blooms
When the soil runs too rich or the spot sits in shade, cardinal climber throws everything into leaf and skips the flowers. Too much nitrogen drives this, so cut the feeding and shift or train the vine into full sun. Lean, well-drained ground plus bright light coaxes those red trumpets right back out.
Fix:
- Stop high-nitrogen feeding
- Move or train the vine into full sun
- Grow in leaner, well-drained soil
Surprise seedlings springing up next year
Warm-climate gardeners watch this vine self-seed freely, with dropped seed sprouting right where it grew the year before. Yank out any volunteers you didn't plan for. For a real fix, clip the green seed pods before they ripen and fling their seed around.
Fix:
- Pull unwanted seedlings
- Remove developing seed pods before they mature and drop
Toxicity
Treat this as a toxic plant, with the hazard concentrated in the seeds. They carry indole alkaloids of the LSA type that can bring on stomach upset and, in larger doses, agitation and hallucinogenic effects in pets, livestock, and people. The foliage rates as a milder caution, so keep the seeds and seed pods well clear of animals and children.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Mild
Nibble a few leaves and a cat usually walks away with a queasy stomach and some vomiting. The seeds carry the real punch, and a mouthful can spark agitation, tremors, and disorientation.
Dogs Mild
Chewed foliage tends to bring on drooling and a round of vomiting. Let a dog swallow the seeds, though, and it can grow restless, shaky, and plainly off.
Horses Mild
Horses count this plant as toxic, since the seeds pack the alkaloids that upset the gut and, in quantity, hit the nervous system. Steer grazing horses clear of the vine and its seed pods.
Rabbits Caution
The same seed alkaloids that trouble cats and dogs would land hard on a small grazer, so treat this vine as strictly off-limits for rabbits rather than safe browse.
Livestock Caution
Graze on the seeds or seed pods and goats, sheep, and cattle can take in the LSA-type alkaloids, which risks stomach and nervous-system trouble. Fence it well away from pasture.
Birds Caution
The seeds carry the hazardous compounds, so block poultry and pet birds from pecking the pods even though the foliage rates as a lesser worry.
People Caution
Nobody grows any part of this vine to eat. The seeds hold indole alkaloids that can trigger 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 learning belong to its two parents. Both show up in gardens and reveal exactly where this vine picked up its looks.
Ipomoea quamoclit (cypress vine)
Half the hybrid's parentage, sporting very fine thread-like leaves cut into needle-thin segments that read far more fern-like than the cardinal climber's own foliage.
Ipomoea coccinea (red morning glory)
The vine's other parent, a red-flowered morning glory that keeps its broad, heart-shaped leaves whole rather than finely cutting them.
How to propagate
Cardinal climber sprouts readily from seed, and seed is the only route to start it. The whole knack lies in 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
Raise cardinal climber from seed, kicking it off indoors 4 to 6 weeks before your last frost or sowing it outside once the soil warms up. That seed coat is tough, so nick it and soak the seeds overnight before sowing to get even sprouting. Seedlings push up in 5 to 10 days, then spend a few more weeks before they reach for a support and start to climb.
Myths
Cardinal climber, cypress vine, and cardinal flower are all the same plant.
Cardinal climber springs from a cross of cypress vine and red morning glory, and its deeply lobed, palmate leaves land squarely between the two parents in shape. Cypress vine shows finer thread-like foliage, while red morning glory spreads 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.