Ornamental · Convolvulaceae
Moonflower
Ipomoea alba
Plant it in full sun and warm soil, and moonflower flings open fragrant white trumpets every evening.
Full sun
Every 3–7 days
50–90°F · 10–32°C
60–120 days
Overview
Moonflower is a fast, twining vine that lives for one nightly performance. The moment dusk lands, fat buds spiral wide into pure-white, fragrant trumpets as broad as a saucer, calling in the sphinx and hawk moths that pollinate them before the flowers wrap up by morning. It runs in the morning glory family and shares their easygoing habit, just flipped onto the night shift, which makes every evening in the garden feel like an event.
Feed it heat and a solid support and it climbs hard, clearing head height in a single season and turning a bare fence into a green wall in weeks. It counts as a tender perennial in frost-free ground, though most growers run it as an annual and sow fresh seed every spring. Those scented evening flowers earn it a spot on porches, arbors, and any corner worth lingering in after dark.
Best of all, it asks for next to nothing once it gets rolling. The only two things that trip it up are a cold, short season and overly rich soil, either of which hands you a wall of leaves and hardly a flower. Nail the warmth and the lean soil, and from there the job is mostly giving it something to climb and standing back.
Care
The short version: full sun, warm and average (not rich) well-drained soil, and steady moisture, with a strong trellis or fence for the vine to climb.
Light
Hand moonflower full sun, ideally 6 or more hours a day, and it repays you. It shrugs off a little afternoon shade, but anything less than full sun slows the vine and cuts your flower count.
Water
Keep the soil evenly moist and never soggy, watering roughly every 3 to 7 days as the heat and rain dictate. Steady, medium moisture keeps it charging along, and well-drained ground keeps the roots thriving.
Soil
Plain, well-drained soil is all it craves, whether loam, clay, or sand, at a pH from 6.0 to 7.8. Skip the rich, heavily amended beds, since lush soil piles on leaves and drags the flowers back.
Temperature
This is a bona fide heat lover, cruising from 50°F to 90°F (10°C to 32°C). It hits full stride in the swelter of high summer and folds at frost, which ends the plant flat.
Humidity
Everyday outdoor humidity is plenty, so there is no number to hit. The vine takes typical garden air in stride and asks for nothing extra here.
Feeding
A light, balanced fertilizer about once a month through the growing season keeps it powering on. Ease off the nitrogen above all, since a heavy hand pumps out foliage and pushes the blooms back.
Pruning
Pinch out the young tips early to send the vine branching and filling out. After that, snip away any dead or stray growth and keep steering the stems onto their support as they scramble up.
Repotting
In a container, plan to bump it up once a year. Watch for roots circling the pot, breaking out the drainage holes, or growth that stalls, all shouting that the plant wants more room.
Size & spacing
This is a big, ambitious vine, climbing 10 to 30 feet (3 to 9 m) in a strong season and spreading 3 to 6 feet (91 to 183 cm) wide. Hand it a tall, sturdy trellis, fence, or arbor and turn it loose.
When to plant
Moonflower thrives on a long run of warmth and quits at the first frost, so timing is where the fun starts. Nick and soak the hard seeds, start them indoors 6 to 8 weeks before your last frost, and turn the plants loose outside once the cold clears. From there it blooms from mid-summer into fall.
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 last spring frost, after nicking and soaking the hard seed coat
- Plant: 1-2 weeks after last spring frost once soil is warm
- Harvest: Mid-summer into fall; flowers open at dusk and close by morning
Hardiness
USDA hardiness zones: 10–12
Temperature: down to -1°C
Troubleshooting
Moonflower throws very few curveballs, and most of them trace straight back to the weather or the soil. The usual gripe is leaves without flowers, with the odd pest dropping by. Match what you spot below and jump on it early.
Leaves racing ahead while the flowers lag
A moonflower that piles on green growth but skips the buds has almost always run short on warm weeks or landed in soil that is far too rich. Excess nitrogen fuels leaves and stalls the flowers, and shade only drags things out further. Push it into full sun, dial the feeding right back, and start seed early so the vine sprints to bloom before the season closes.
Fix:
- Site in full sun with a sturdy support
- Avoid rich soil and high-nitrogen fertilizer
- Start seed indoors early in short-season areas to extend the warm growing window
Kinked shoots, speckled leaves, or a hint of webbing
Twisted tips and speckled leaves usually mean aphids and spider mites have moved in, with a caterpillar or leaf miner joining the party now and then. Scout the leaf undersides and the soft new tips, where aphids cluster and mites spin a fine web across the fading, stippled patches. Hit them with a hard jet of water, follow up on the soft-bodied ones with insecticidal soap, and flick off caterpillars by hand. A vigorous vine powers right through all of it.
Fix:
- Dislodge aphids and mites with a strong spray of water
- Treat soft-bodied pests with insecticidal soap
- Handpick caterpillars and remove mined leaves
Toxicity
Give the seeds real respect. Like every morning glory, moonflower loads LSA alkaloids into its seeds, which can sicken pets, livestock, and people and set off a hallucinogenic reaction if eaten. The leaves are a much milder concern, but keep the seeds and pods well clear of animals and children.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Mild
The seeds are what to guard against with cats, since they pack the LSA alkaloids. A small nibble tends to trigger drooling and vomiting, and a bigger dose can bring on tremors, a wobbly walk, and disorientation. The leaves rate as a much milder worry.
Dogs Mild
A dog that gulps down the seeds usually lands an upset stomach and vomiting. Push the amount higher and those same alkaloids can spark agitation, tremors, and a spaced-out, hallucinogenic reaction. Foliage by itself rarely stirs up more than mild stomach upset.
Horses Caution
A horse rarely bothers with the vine, but the seeds carry the same alkaloids that hit other animals. Keep them clear of the seed pods, and stay alert for colic or dullness if any get eaten.
Rabbits Caution
Never toss moonflower to a rabbit as forage. The seeds especially can throw a rabbit's gut off, so keep the plant and its pods well clear of the hutch and run.
Livestock Caution
Cattle, goats, and sheep tend to steer around the bitter vine, yet the seeds still deserve caution. Fence stock away from any plants setting pods to stay on the safe side.
Birds Caution
Here too the seeds top the watch list. Keep pet birds away from any that drop, since eating them can spark vomiting and a jittery, disoriented spell.
People Caution
No part of this vine is food, and the seeds hold the danger. Eating them brings on nausea, vomiting, and hallucinogenic effects from the LSA alkaloids, so stash seeds and pods well out of children's reach.
Keep seeds out of reach of pets and children; ingestion of large amounts of seeds can cause neurologic signs.
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
There is truly just one moonflower, the species itself, and it shines even brighter grown next to a day-blooming relative. Here are the two worth chasing down.
Ipomoea alba (species moonflower / moonvine)
This is the true moonflower, a vine that flings open fragrant, pure-white trumpets up to 4 to 6 inches across at dusk for the sphinx and hawk moths to pollinate.
Day-blooming morning glory (Ipomoea purpurea / Ipomoea tricolor)
This close cousin earns a spot right beside moonflower to keep flowers coming, since its colorful blooms fire up through the day rather than at night.
Companions
Moonflower pairs naturally with its day-blooming morning glory cousins, which fill the trellis with color while the moonflower sleeps and then hand the night shift back over at dusk.
Plant near
Day-blooming morning glory (Ipomoea purpurea/tricolor): Planted together they provide round-the-clock flowers, day and night.
How to propagate
Moonflower springs from seed, and the one move that matters is coaxing that tough seed coat to let water through.
SeedEasy
Start indoors 6-8 weeks before last frost or sow outdoors after frost when soil is warm · 1-3 weeks to germinate; rapid growth once weather warms
Moonflower takes off from seed with barely any coaxing, once you crack open that stubborn seed coat. Nick it with a knife or scuff it on sandpaper, then soak the seed overnight before it goes in the ground. Start it indoors 6 to 8 weeks before your last frost, or sow it straight outside once the soil warms, and watch it sprout in 1 to 3 weeks before it rockets upward in the heat.
Myths
The vining moonflower is the same deadly plant as the jimsonweed or thorn apple that shares its name.
These are two unrelated plants that just happen to share the name moonflower. The vine here is Ipomoea alba, a twining morning glory whose seeds hold mildly toxic LSA alkaloids. The truly dangerous one is Datura, an upright nightshade whose tropane alkaloids, atropine, scopolamine, and hyoscyamine, can be fatal. Datura is by far the more poisonous of the two, so the shared name alone tells you nothing about the risk.