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 feet long in just one season under optimal conditions.
|Botanical Name||Ipomoea alba (formerly Calonyction aculeatum)|
|Common Names||Moonflower, tropical white morning-glory, moon vine, evening glory, moon creeper|
|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 (USDA)|
|Native Area||North America, Central America, South America|
|Toxicity||Toxic to people and animals|
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 air flow 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.
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 on the vine 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 your seedlings to direct sunlight for longer stretches each day. After about a week of this, the seedlings are ready to be planted outdoors.
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