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Planting, Growing, and Caring for Moonflower Vines
Gorgeous, graceful, and fragrant, moonflowers provide an atmosphere of romance and mystery wherever you grow them. Learn how to plant, grow, and care for moonflowers.
About Moonflowers
If you search online for moonflowers, one of the first things you’ll notice is little agreement on what a moonflower is. Both plants of the Datura genus and members of the Ipomoea genus go by the common name of moonflower, as well as tropical white morning glory and moon vine.
We’re talking about Ipomoea alba, also known as Ipomoea noctiflora. The Plants of the World Online database maintained by the Royal Botanical Gardens recognizes the two species as synonyms. With that cleared up, we’ll just call them moonflowers. They’re a tender perennial vine hardy only in USDA zones 10 to 12, but they can be grown as annuals in other regions.
Moonflowers are prized for their habit of opening only in the evening–hence the name–and for their intoxicating fragrance. The flowers will close again in the morning, spending the day wrapped up like the more familiar morning glories. Their almost luminescent, giant blooms make them perfect for establishing a peaceful evening sitting spot or creating a bit of romance in the garden. See How to Create a Moon Garden.
If you give moonflowers something to climb, you’ll be in for a treat. Their vigorous vines twine around and grow up to 15 feet. Once they start blooming in summer, they’ll continue until autumn frost. The five-inch-wide flowers are bell-shaped and white and appear to glow in the evening. During the day, moonflowers look like a stately dark green vine as the flowers close.
Moonflowers smell sweet to us and pollinators. Moths pollinate at night and are highly attracted to moonflowers, like other bees and insects. Their trumpet-bell-shaped flowers are sometimes visited by hummingbirds as well. See more flowers that attract hummingbirds.
Moonflowers enjoy full sun and won’t mind the more intense afternoon rays. Fertile, loamy soil is best, but they will tolerate most soils if drainage is adequate. A slightly acidic or neutral soil is ideal, but they aren’t picky.
These vines can grow to large, trellis-covering proportions, which requires energy. To give them plenty to work with, provide some finished compost and aged manure in their bed.
Moonflowers can also be grown in large containers and allowed to vine and twine around pergola posts, deck railings, and lattice. Use a pot with good drainage and some mass to anchor it well. For city dwellers, moonflowers make a fantastic scented privacy screen when crawling up a lattice or trellis support on your deck or patio.
When to Plant Moonflowers
You may start moonflower seeds indoors 4 to 6 weeks before your last frosts. Or, in warmer areas, sow them directly in the ground.
They can be transplanted out or directly seeded after all danger of frost has passed and the soil has warmed. Remember, these are tropical plants, and they won’t grow much in cooler weather.
How to Plant Moonflowers
- Moonflower seeds have a hard coating, so nick them with a nail file or soak them for 24 hours to aid germination.
- The seeds won’t germinate in cold soil (this is a tropical plant), so if sowing outdoors, wait until soil temps are about 70 to 80 F. Many gardeners have better luck starting them indoors first.
- Plant about ¼ inch deep in individual cells or small pots. Keep moist and warm.
- Before transplanting or direct seeding, prepare the bed by working in a layer of compost.
- Harden off seedlings for 7 to 10 days before transplanting.
- If direct seeding, sow seed 1/2 inch deep. Space seeds about four inches apart.
- Install the trellis or arbor (if not planting near something to climb) when you direct sow or transplant to avoid damaging roots later.
Ipomoea alba (white moonflower ). Credit: Lee Risar
Once they germinate and get growing, moonflowers are pretty carefree. They’ll seem to grow slowly at first and then take off. Keep them neat and stunning by giving them something to climb, or they may sprawl around and cause a fuss.
- Moonflowers prefer consistently moist soil, but don’t overdo it. If in doubt, stick your finger in the soil. If it feels dry past the first knuckle, give them a drink.
- Mulch moonflowers (huzzah for mulch!) to maintain soil moisture and minimize dry periods.
- Deadheading moonflowers will encourage more blooms, but they’ll keep flowering if you miss a few. Remove them before they develop seeds if you live in warmer climates where these vines are perennial, as they can spread.
Andy Wilcox
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