Moonflowers have long fascinated gardeners with their ethereal beauty and night-time blooming. Known by its botanical name Ipomoea alba, this tender perennial vine adds a touch of mysticism to your garden, while evoking a romantic atmosphere with its sweet fragrance and bright flowers. Learning how to grow moonflowers will benefit your garden year after year.
“What's unique about the moonflower is that its 5- to 8-inch flowers begin to bloom at dusk and only bloom for the night. It's magical to see these large white blooms in the evening light,” says Bruce Bennett, certified professional horticulturist at Gardens by Design in Seattle, Washington.
Growing moonflower in your own garden requires patience, care, and a little know-how, but it can be a satisfying experience. This guide will show you everything you need to know about growing moonflower, from choosing the right location to nurturing it until it blooms in full bloom.
More inspiration for your garden:
What is a Moonflower?
Native to tropical and subtropical regions of North and South America, the moonflower is a climbing plant that belongs to the Convolvulaceae family, which also includes the noxious weed known as morning glory. Unlike its diurnal cousins, the moonflower blooms only at night and gives off a delicate fragrance when in bloom.
“The sweet scent of honeysuckle combined with vanilla attracts nocturnal pollinating insects such as moths, bats, beetles and even hummingbirds,” Bennett says.
This fast-growing vine can reach impressive heights, often climbing over trellises, fences and arbors with ease. “The vines become twining and can grow up to 15 feet,” says Bennett. With their heart-shaped leaves and large, trumpet-like flowers, moonflowers are a spectacular sight, especially when they open in the moonlight on warm summer nights.
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How to Grow Moonflower
position
“These vines will grow outdoors as perennials in USDA hardiness zones 10 through 12,” says Bennett. “If it's colder, treat them as annuals or as potted plants that you bring indoors for the winter.” Moonflowers like direct sunlight and don't mind some strong afternoon sun, so choose a spot in your garden that gets at least six to eight hours of direct sunlight each day.
Caution: Moonflower is poisonous if ingested, so make sure to plant it away from where pets and children play.
soil
The key to knowing how to grow moonflower is to ensure the soil has good drainage.
“Moonflower prefers a neutral, loamy soil, but the plants will thrive as long as the soil is good and drainage is good,” says Bennett, who recommends preparing your garden by amending the soil in a 4-foot circle where you'll plant the vines with one part perlite or vermiculite and two parts compost to improve drainage.
timing
Moonflowers can be grown from seed or seedlings, but many gardeners prefer to grow them from seed for a more economical and satisfying experience. To plant moonflower seeds, wait until after the last spring frost so the soil has warmed.
“Most parts of the country don't get as much heat as this plant likes, so it's best to sow the seeds indoors six weeks before transplanting outdoors in mid-May,” says Bennett. “Once the plants get over the trellis posts, the large leaves will appear, and finally, in late August, the buds will start to appear. In mid-September, the flowers will start to open as evening approaches. The buds open quickly, which is exciting to watch, and by dawn the next day, the flowers will have faded.”
Seed germination
Once the seeds sprout and start growing, moonflowers are low-maintenance, Bennett says. They may seem slow at first, but then they'll explode with growth.
Tips for growing moonflower seeds:
Soak the seeds in water overnight to soften the tough outer shell. Use nail clippers to cut off the ends of the seed shell to make it easier for the new plants to grow. Whether sowing seeds or transplanting seedlings, wait until the soil temperature is close to 70 degrees Fahrenheit. Seeds will not germinate in cold soil. Plant seedlings about 1/4 inch deep in individual cells or small pots. Keep moist and warm. Allow the vines to climb to help them look their best; otherwise, they may stretch and collapse under their own weight. Dead-picking moonflower flowers will produce more flowers, but there is no need to pick them one by one. If you miss a few, the flowers will continue to bloom.
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How to care for your moonflower
Once your moonflower seeds have germinated, it's important to provide them with proper care so that the plants will thrive.
water
“Since these vines actively grow during the warmer months of the year, consider giving them five gallons of water once a week,” says Bennett. “One of the easiest ways to do this is to drill a few holes into the outside edge of the bottom of a five-gallon container, fill the container with water, and leave it until the next week,” he says.
fertilizer
If you amend the soil with compost before planting, that's all you need, but if not, Bennett recommends working a slow-release organic fertilizer around the plants in May.
Support Structure
Moonflower is a vigorous climbing plant that will quickly scale nearby structures in search of sunlight. Young seedlings will thrive if they have something to climb, such as a trellis or wire mesh. As the seedlings grow, thin them out to allow each plant enough space to thrive. Regularly check the stability of the support and make any necessary adjustments to keep your moonflower vines safe.
“Remember, vines can grow up to 15 feet tall and six feet wide,” Bennett says.
pruning
To improve flowering, Bennett recommends removing as many of the dead flowers as possible. “Pruning is limited to aesthetic purposes, to tie down vines or to redirect growth energy,” he says.
Pest Management
Moonflowers are relatively resistant to pests and diseases, but you may encounter common garden pests such as aphids, spider mites, and whiteflies.
“A strong blast of water from a hose will eliminate most of these pests, but for more persistent infestations, neem oil or insecticidal soap can help,” Bennett says.
Additionally, be sure to practice good garden sanitation, such as removing fallen debris and diseased plants, to prevent the spread of bacteria.
When is Moonflower's growing season?
Bennett said if you plant the plants in May, they should start blooming in late August and continue to bloom through October.
The flowers usually begin to open in the late afternoon, reaching their peak fragrance and beauty after nightfall. Take the time to admire the delicate petals, which range in color from pure white to pale pink, and inhale their lovely fragrance. Feel free to snip off a few flowers to enjoy indoors or share with friends, but be sure to leave plenty on the vine to attract pollinators and ensure abundant blooms throughout the growing season.
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