Ornamental · Convolvulaceae
Cardinal Climber
Ipomoea × multifida
Give it full sun and lean soil and this gentle, fast-growing vine rewards you with scarlet trumpets that hummingbirds chase all summer long.
Full sun
Every 3–7 days
50–95°F · 10–35°C
60–75 days
Overview
If you are new to vines, cardinal climber is a kind place to start. It twines quickly and will cover a trellis or fence in a single season without much fuss. A member of the morning-glory family, it comes from crossing cypress vine with red morning glory, and that pairing gives it deeply cut, palmate green leaves and small, bright red trumpet flowers that hummingbirds simply cannot pass by.
Climbing comes naturally to this vine, and it can reach 6 to 15 feet (1.8 to 4.5 m) over a warm summer, so all it really wants from you is something to grab onto from day one. It stays perennial only in the warmest zones and is happily grown as an annual nearly everywhere else, sown fresh each spring once the frost has gone.
The lovely part is how little it asks. Full sun and ordinary, well-drained soil are all it needs, and you can relax, since the most common mistake is being too generous, which gives you leaves instead of flowers. The one habit to keep a friendly eye on is its eagerness to self-seed, which may hand you a few volunteers the following year.
Care
The short version: full sun, average to lean well-drained soil, and about an inch of water a week. You can skip the fertilizer altogether, just give it a support to climb, and pull the green seed pods if you would rather it not spread.
Light
Give cardinal climber full sun and you will be rewarded with the fullest show of flowers. It will still grow in partial sun or light shade, but every hour of shade trades blooms for more leaf, so a bright, open spot is the kind choice for both of you.
Water
Aim for about 1 inch of water a week and keep the soil evenly moist while the young vine is settling in. Once it is established it shrugs off short dry spells, so the occasional missed watering is nothing to fret over, though 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 actually works against you here by pushing lush vine and few flowers, so feel free to hold back on the compost.
Temperature
This is a warm-weather vine that is happiest between 50°F and 95°F (10°C to 35°C). It needs warm soil to wake up and frost will end its season, so there is no advantage in rushing it outside early.
Humidity
Ordinary outdoor air suits it just fine, so you have no humidity target to chase. The one thing that helps is good airflow, which keeps the dense foliage from giving pests a place to settle in.
Feeding
It barely needs feeding at all, which makes life easy. Skip fertilizer in decent soil, and in very poor ground reach only for a light balanced feed, because high nitrogen gives you leaves instead of flowers.
Pruning
Pinch the young tips to coax the vine into branching fuller, and gently train or trim it onto its support as it climbs. Snip off the green seed pods whenever you want to keep it from self-seeding.
Repotting
Grown as an annual, it lives a single season and is not carried over, so there is no repotting in the usual way. In a container, the simplest path is to start fresh each spring in new soil rather than reusing a rootbound pot.
Size & spacing
Look for 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 breathing room so air can move freely through the foliage.
When to plant
Cardinal climber loves warmth and simply will not stand up to frost, so timing is your friend here. Start the seeds indoors a few weeks ahead of your last frost, set the young plants out once the soil has warmed through, and you will enjoy blooms from summer all the way 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 causes any real worry, and the few hiccups that do come up show themselves in the flowers, the foliage, or as a scatter of stray seedlings. Catch the early signs and you can put things right long before the vine spreads or sulks. Find what you are seeing below, then take a small step to fix it.
Speckled, nibbled leaves with a sticky film
A few pests do find this vine, but they are easy enough to manage once you spot them. Sap-feeders such as aphids and spider mites, along with chewers like Japanese beetles and leaf miners, are the usual visitors. Turn the leaves over and look at the new growth to find which one you have, then rinse them off with a strong jet of water or treat with insecticidal soap or horticultural oil. Pick beetles off by hand and pull away any mined or badly chewed leaves, and the vine bounces back.
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
Loads of leaves, hardly a flower in sight
Take heart, this is one of the easiest problems to turn around. When the ground is too rich or the spot is too shady, the vine simply pours itself into greenery, and too much nitrogen is almost always behind it. Stop the feeding and move or train the vine toward full sun, and you will see those red trumpets return on lean, well-drained ground.
Fix:
- Stop high-nitrogen feeding
- Move or train the vine into full sun
- Grow in leaner, well-drained soil
Surprise seedlings showing up the next year
There is nothing to worry about here, just a vine that self-seeds freely, especially where summers run warm, with dropped seed sprouting right where the plant grew before. Simply pull up any volunteers you would rather not keep. For a lasting fix, snip the green seed pods off before they ripen and scatter, and the problem quietly takes care of itself.
Fix:
- Pull unwanted seedlings
- Remove developing seed pods before they mature and drop
Toxicity
This is a toxic plant, and the danger is tucked 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 leaves are a milder caution, so the main thing is to keep the seeds and seed pods well away from animals and children.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Mild
A curious cat that tastes the leaves will usually just have a queasy stomach and some vomiting. The seeds are where the real trouble lies, and a mouthful of those can bring on agitation, tremors, and disorientation, so keep them out of reach.
Dogs Mild
If your dog chews a few leaves, expect a little drooling and a round of vomiting and not much more. The seeds are another matter, since eating them can leave a dog restless, shaky, and clearly unwell.
Horses Mild
Horses are on the list of animals this vine can affect, with the seeds holding the alkaloids that upset the gut and, in larger amounts, the nervous system. Keep grazing horses away from the vine and its seed pods to stay on the safe side.
Rabbits Caution
The same seed alkaloids that bother cats and dogs would land much harder on a small grazer, so it is best to treat this vine as off-limits for rabbits rather than as safe nibbling.
Livestock Caution
Goats, sheep, and cattle can take in the LSA-type alkaloids if they graze the seeds or seed pods, which puts their stomach and nervous system at risk. Fencing it away from pasture keeps everyone safe.
Birds Caution
The hazardous compounds sit in the seeds, so the wise move is to keep poultry and pet birds from pecking the pods, even though the foliage itself is a smaller concern.
People Caution
No part of this vine is meant to be eaten. The seeds carry indole alkaloids that can cause stomach upset and hallucinogenic effects, so keep them well out of the 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
Because cardinal climber is a hybrid, the names most worth knowing are its two parents. Both show up in gardens, and each one helps explain where this vine gets its good looks.
Ipomoea quamoclit (cypress vine)
One of the two parents behind the hybrid, easy to spot by its very fine, thread-like leaves split into needle-thin segments that read 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 you can recognize by its broad, heart-shaped leaves that stay whole rather than being finely cut.
How to propagate
Cardinal climber grows easily from seed, which happens to be the only way it is started. The single trick to learn is getting past its tough seed coat, and that part is simple once you know it.
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
Growing cardinal climber from seed is wonderfully simple, and you can begin indoors 4 to 6 weeks before your last frost or sow straight outside once the soil has warmed. Because the seed coat is hard, give each seed a small nick and soak them overnight before sowing, and you will get nice even germination. Look for seedlings to push up in 5 to 10 days, with a few more weeks before they reach up and start to climb.
Myths
Cardinal climber, cypress vine, and cardinal flower are all the same plant.
Here is the gentle untangling: cardinal climber is a hybrid of cypress vine and red morning glory, and its deeply lobed, palmate leaves sit right between the two parents in shape. Cypress vine wears 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.