Ornamental · Convolvulaceae
Cypress Vine
Ipomoea quamoclit
Hand it full sun and a string to climb, and cypress vine returns feathery leaves and scarlet stars.
Full sun
Every 3–7 days
59–95°F · 15–35°C
65–90 days
Overview
Cypress vine is a quick-growing annual in the morning-glory family, prized for its lacy, thread-fine leaves and small scarlet star-shaped flowers. The foliage is slit so finely it reads almost fern-like, and the stars pull in hummingbirds and butterflies from early summer to frost. Set against a support, it winds upward 6 to 20 feet (1.8 to 6 m) in one season.
It ranks among the simplest vines to raise, which is both the appeal and the snag. Hand it a sunny corner and something to grip, and it climbs away under its own steam. It also sheds seed liberally, so across warm regions it naturalizes and surfaces in spots you never sowed.
Its hard seed is the part to mind. The seeds carry LSA-type alkaloids and are toxic to pets and people if swallowed, so place the vine and tuck away any gathered seed out of reach. Raise it for the display, never for the pods.
Care
The short version: full sun, lean to average well-drained soil, and even moisture while it takes hold. Hold off on fertilizer, hand it a trellis or string to wind up, and snip the seedpods if you would rather it not sow itself across the bed.
Light
Cypress vine sets the most flowers in full sun, which means 6 or more hours of direct light each day. It still winds up in part shade, though the stars thin quickly as the light fades.
Water
Hold the soil evenly moist while the vine roots in, then taper off, since it weathers some drought once it has anchored. Soak it deeply through dry stretches instead of frequent shallow sips.
Soil
Set it in average to poor, well-drained soil and skip the temptation to enrich it. Rich earth or added nitrogen drives leafy growth over flowers, so lean ground serves it better. It accepts a pH across 6.0 to 7.5.
Temperature
This is a heat seeker that runs through the warm months and falls at frost. It grows across roughly 59°F to 95°F (15°C to 35°C) and stalls until the soil has warmed.
Humidity
Plain outdoor air suits it well, so there is no level to fuss over. Steady airflow counts for more than any figure, keeping the thread-fine leaves clear of pests and mildew.
Feeding
Feeding mostly works against this vine. It calls for almost none, and high-nitrogen feed leaves you a curtain of leaves with few stars, so at most give a light low-nitrogen feed at planting in genuinely poor soil.
Pruning
Pinch the young growing tips to send the vine into branching, and trim straying stems to keep it in place. As the season closes, clear the spent stems and snip the seedpods to curb its heavy self-sowing.
Repotting
none
Size & spacing
With support, the vine winds 6 to 20 feet (1.8 to 6 m) tall and reaches 3 to 6 feet (91 to 183 cm) across. Set up a strong trellis, fence, or string, since it blankets ground quickly once the heat lands.
When to plant
Cypress vine is a warm-season annual with no tolerance for cold soil. Start the seed indoors in late winter or drop it outside once frost has passed, and the vine flowers from early summer until the first autumn frost lays it down.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: 6-8 weeks before the last spring frost; nick and soak the hard seed coat 12-24 hours before sowing.
- Plant: After the last frost when soil has warmed; can be direct-sown at the last frost date.
- Harvest: Early summer through fall frost.
Hardiness
USDA hardiness zones: 11–12
Temperature: down to 4°C
Troubleshooting
Cypress vine asks for little fuss, and most snags trace back to overfeeding, too much shade, or a handful of common pests on the fine leaves. Match what you see below, then treat the cause rather than the symptom.
Drifts of unplanned seedlings the next spring
This vine is a heavy self-sower and turns weedy in warm regions, scattering seed that sprouts in thick patches the season after. Lift the volunteers while their roots are still shallow and they pull easily. The surest way to stay ahead is to snip the swelling seedpods before they dry and split open.
Fix:
- Pull volunteer seedlings while young
- Remove seedpods before they ripen and shed seed
A wall of green leaves and hardly a single star
When the soil is too rich and nitrogen runs high, the vine pours its energy into thread-fine leaves and twining stems instead of buds, so it climbs hard and barely shows a flower. Deep shade has the same effect, because the plant wants at least 6 hours of direct sun before it sets blooms freely. Cut the feeding, shift it into full sun, and grow it in lean, well-drained ground.
Fix:
- Stop nitrogen feeding
- Move or sow in a full-sun site (6+ hours direct sun)
- Grow in average to lean, well-drained soil
Pinpricked, twisted leaves dusted with webbing or stickiness
The delicate, feathery leaves attract aphids, spider mites, and leaf miners, which speckle and yellow the foliage, coat it in sticky film, or etch pale winding tunnels through it. Turn a few leaves over and study the underside: soft clustered bodies are aphids, faint webbing means mites, and twisting trails mean miners. Hit them early with a sharp rinse of water and insecticidal soap, then pull off any leaves heavily tunneled.
Fix:
- Rinse foliage with a strong spray of water to dislodge mites and aphids
- Apply insecticidal soap, treating early before populations expand
- Remove and destroy heavily mined or infested leaves
Toxicity
This vine does not belong within reach of pets or small children. The seeds hold LSA alkaloids and are toxic if swallowed, bringing stomach upset and, in larger amounts, hallucinations and other nervous-system effects. The thread-fine foliage rates as a milder caution, but the seedpods carry the real danger, so keep them and any saved seed well out of reach.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Mild
A cat that chews on the lacy leaves may drool or be sick. The seeds are where the real risk sits, since they hold LSA alkaloids that can spark agitation, tremors, disorientation, or hallucinations once a cat swallows more than a couple.
Dogs Mild
Nibbled foliage tends to bring on vomiting and a spell of upset stomach. Swallowing a handful of seeds is the larger concern, because the alkaloids can set off restlessness, shaking, and an unsteady, confused dog.
Horses Caution
Horses seldom graze the thread-thin leaves, yet the same morning-glory seeds belong out of reach. A mouthful of seed could disturb the gut and, in larger doses, reach the nervous system.
Rabbits Caution
Rabbits should not browse this vine. Treat the seedpods as the danger, since the alkaloid-loaded seeds can upset digestion and, in bigger amounts, bring neurologic effects.
Livestock Caution
Grazing stock usually pass the vine by, but seed-bearing plants standing in a pasture call for care. Eating the seeds can bring stomach upset and, with enough, signs of nervous-system trouble.
Birds Caution
Wild birds sip nectar from the scarlet stars without harm, yet the seeds are not safe to feed. Keep gathered seed clear of pet birds, where even a little could cause trouble.
People Caution
No part of this vine is grown for the table. The seeds are the problem: eating them can bring nausea and stomach pain, and a larger dose of the LSA-type alkaloids can set off hallucinations. Keep seeds and pods far from children.
Keep seeds and seedpods away from pets; the seeds are the main concern.
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
Cypress vine itself is the scarlet-flowered standard, yet a pair of close kin show up beside it and are simple to confuse.
'Alba'
A white-blooming selection whose stars come out clean white rather than the usual scarlet.
Cardinal Climber (Ipomoea × multifida)
A cross of I. coccinea and cypress vine carrying wider, deeply lobed leaves and red trumpet flowers with pale throats, unlike the threadlike leaves of cypress vine.
How to propagate
Cypress vine arrives by seed alone, and the single trick worth learning is loosening that hard seed coat before sowing.
SeedEasy
Sow indoors 6-8 weeks before last frost, or direct-sow after the last frost when soil is warm. · Germinates in about 1-3 weeks after scarifying; establishes and climbs quickly through the warm season.
This vine sprouts from seed with little effort, though the tough coat asks for a head start. Scratch or nick each hard seed and let it soak for 12 to 24 hours before planting, then begin indoors 6 to 8 weeks ahead of your last frost or drop seed straight into warmed ground after it. Sprouts break in 1 to 3 weeks, and the vine races upward once the warmth arrives.
Myths
Cypress vine and cardinal climber are one and the same plant.
These are two separate vines. Cypress vine wears extremely fine, feathery, thread-like leaves slit nearly to the midrib, while cardinal climber, the hybrid bred from crossing I. coccinea and I. quamoclit, carries wider, deeply lobed palmate leaves. The leaves tell them apart.