Moonflower is a tender perennial vine that can add incredible beauty and powerful fragrance to a night garden. Often grown as an annual outside of its tropical and subtropical growing zones, this vine features large, heart-shaped, dark green leaves on robust, slightly prickly stems. Its trumpet-shaped flowers begin blooming in mid-summer and last until fall. They are typically an iridescent white and grow around 6 inches long and 3 to 6 inches wide. The blooms unfurl from cone-shaped buds as the sun goes down, as well as on cloudy days. They stay open all night, exuding their sweet fragrance into the air, before closing up again the next morning.
Moonflower is best planted in the spring after the danger of frost has passed. It is a fast-growing vine and can reach around 10 to 20 feet long in just one season under optimal conditions. Moonflower is toxic to humans and animals, like its cousin morning glory.
|Common Names||Moonflower, tropical white morning-glory, moon vine, evening glory, moon creeper|
|Botanical Name||Ipomoea alba (formerly Calonyction aculeatum)|
|Mature Size||10–15 ft. tall, 3–6 ft. wide|
|Soil Type||Moist, well-drained|
|Soil pH||Acidic, neutral|
|Bloom Time||Summer, fall|
|Flower Color||White, purple|
|Hardiness Zones||10–12 (USA)|
|Native Area||North America, Central America, South America|
|Toxicity||Toxic to dogs, cats, and humans|
Moonflower vines require fairly simple maintenance with regular watering and feeding, and they rarely have serious pest or disease problems. Because they have a climbing growth habit, it’s ideal to provide them with a trellis or other support structure they can grow around. They also can be allowed to spread naturally as a ground cover or grown in hanging baskets and containers. If possible, plant them near a deck or bedroom window where you can enjoy their sweet fragrance at night.
If you don’t want the vines to reseed in your garden, remove the spent flowers before they can drop seeds. This deadheading process also can promote further blooming on the vines. When growing moonflower as an annual, most gardeners prefer to start new plants the following year rather than trying to overwinter their plants; the vines can be difficult to maintain indoors. When grown as a perennial, the vines can be pruned back and shaped as needed in the fall. Thin the stems to improve airflow around the plant and open it up to sunlight.
Moonflower grows best in full sun, meaning at least six hours of direct sunlight on most days. It can adapt to partially shady conditions, though it might not flower as well.
This vine can tolerate a variety of soil types. But it prefers a rich, loamy soil with good drainage and a slightly acidic to neutral soil pH.
Moonflower likes a moderate amount of soil moisture. Water young plants regularly, so their soil stays moist but not soggy. Soil that's too wet can cause the roots to rot. Then, water established plants when the soil begins to dry out. The vine will tolerate short periods of drought, but a long dry spell can kill it.
Temperature and Humidity
These vines thrive in the warmth and humidity of their growing zones. If you live in a cooler climate, wait to plant them outside until the temperature is reliably around 60 to 70 degrees Fahrenheit. Make sure their soil stays moist if your area is experiencing extreme heat or dry conditions.
Fertilize every three to four weeks with a half-strength, high-phosphorus fertilizer when the plant is in bloom. Avoid high-nitrogen fertilizer, as it can promote foliage growth at the expense of blooms.
Types of Moonflower
In general, Ipomoea alba is sold without a variety designation. Some similar plants that also use the common name moonflower include:
- Ipomoea leptophylla: This is an erect, flowering plant that sometimes goes by the name bush moonflower or bush morning glory.
- Ipomoea violacea: This plant is commonly known as the beach moonflower or sea moonflower, and its white flowers also open at night.
- Datura innoxia: This species features white, trumpet-shaped flowers that bloom at night, and it uses the common names moonflower and pricklyburr.
How to Grow Moonflower From Seed
If you are harvesting seeds from an existing vine, make sure they have fully dried before you collect them. Start seeds indoors roughly four to six weeks before your area’s projected last frost date. Soak the seeds overnight in warm water or slightly nick them with a file to break their hard coating.
Then, plant them about 1/4 inch deep in a seed-starting mix. It’s ideal to use small biodegradable peat pots that you can just bury in the garden, as moonflower doesn’t like its roots disturbed with transplanting. Place the seeds in a warm spot that gets bright, indirect light, and keep the soil lightly moist until seedlings appear. Once outdoor temperatures are reliably warm, you can begin acclimating seedlings to direct sunlight for longer stretches each day. After about a week of this, the seedlings are ready to be planted outdoors.
Common Plant Diseases
Moonflower can fall prey to black rot, which is a bacterial disease that thrives in humid conditions. It can be remedied by separating thick vines to promote air circulation, and never watering from overhead or at night to keep the plant drier.
How to Get Moonflower to Bloom
When beautiful and mysterious moonflower's creamy, white blooms open at night they provide a light, sweet fragrance. The plant produces flowers all summer till the frost: deadhead blooms you can reach, but it will continue to flower if you can't get them all.
Moonflower produces blooms when it's watered regularly. More so, adding fertilizer to your watering routine—moonflower likes a high phosphorous variety—will help your plant produce more flowers.
Common Issues With Moonflower
Moonflower is an easy-going plant that needs very little care. But it can have a few problems that are easy for any gardener to fix.
Yellow Lesions on the Edges of Leaves
This more than likely means your moonflower has black rot, a bacterial disease that if left untreated will force your plant to drop its leaves. But you can fix this because it comes from over-crowding and too much moisture: Untangle your vines to space them out, and never water in the evening or from above.
Seedlings Die for No Reason
This is called damping off and it happens to seemingly healthy seedlings without warning. To keep this from happening, do not over-water seedlings, and do not overcrowd them in your garden. Thin your plants out so they get more air circulation; this should fix the problem.
Can moonflowers grow in pots?
Yes! Plant them the same way you would plant seeds in the ground, and give them something to climb like a tree or a trellis. They will reward you with nocturnal blooms!
What other white flowers go with moonflower?
Many gardeners like to group white flowers together. Great moonflower companions are white-flowering tobacco, star jasmine, or lamb's ear.
Is it easy to gather moonflower seeds?
Like its cousin morning glory, moonflower seeds are super simple to gather. Once a flower has finished blooming, let it get hard and dry—this will take at least several weeks. Once the remains look like a small, dry husk, pull them from the vine. Inside will be seeds ready to plant either immediately or next summer.
Ipomoea alba. Missouri Botanical Garden
Plant problems in cool, wet soil. San Diego State University Extension
Fertilizing Flower Gardens and Avoid Too Much Phosphorus. University of Massachusetts Amherst, Center for Agriculture, Food and the Environment