How to Plant, Grow, and Care for Moon Flower

Moon flower can be a stunning addition to any flower garden. This vining species is a fast grower that will readily attach itself to any type of support structure and create a vertical wall of flowers in your garden. They produce beautiful white flowers that are rounded and can be the size of a salad plate (about six inches in diameter). Although the white variety is probably the most popular, they do come in other colors such as pink, purple, and blue. 

Moon flower is actually a close relative to the sweet potato vine (Ipomoea batatas). Unlike its Ipomoea sibling, I. alba is not edible; like most morning glory species it produces seeds that can be mildly toxic to animals. (Technically speaking, sweet potato seeds shouldn’t be consumed by dogs/cats/horses either, although they’re slightly safer!) On the bright side, it’s fairly easy to keep pets away from moon flower seeds.

There are two other close relatives that fall under the greater category of moon flowers too: Ipomoea leptophylla (aka bush moon flower) and Ipomoea violacea (beach moon flower or sea moon flower). Growing moon flowers is quite easy, and below we’ll discuss their care requirements. 

What is The Moon Flower?

Ipomoea alba, also known as the moon flower plant, moon vine, or tropical white morning glory, is often confused with Datura, which is similar in appearance, but a completely different species and plant type. Daturas exist in the Solanaceae family with deadly nightshade. It is sometimes mistakenly called moon flower but is more often referred to as thornapples, jimsonweeds, and devil’s trumpets. Datura species are highly hallucinogenic, whereas moon flower is not.

Native Area

Moon flowers originated in tropical and subtropical regions of northern and South America. For this reason, the vines grow best in southern zones. They can be grown in a perennial flower garden in USDA zones 9-12. In all other zones it is an annual.

Characteristics

Moon flowers bloom along long vines that put out dark green heart-shaped leaves. These moon flower vines will sprawl along the ground unless they are given a structure to climb. Another way to distinguish between Datura and moon flowers is that Datura flowers bloom during the daytime, whereas moon flower will only begin to bloom in the late afternoon into the night. Moon flowers will begin to close as the sun rises. They may stay open on cloudy days, however.  

Varieties

There are two other types of moon flowers that are a part of the Ipomoea species: bush moon flower and beach moon flower. Bush moon flower, as its name suggests, does not grow as a vine but rather forms a bushy clump. Instead of the standard heart-shaped leaves, they have long slender, thin leaves. Beach moon flower or sea moon flower has thicker leaves and prefers coastal environments such as mangrove swamps. 

Planting

Moon flowers are best grown from seed. Start by soaking the seeds in warm water for 24 hours to soften their hard outer shell. Choose a location with full sun and well-draining soil. Plant the seeds about a quarter to half an inch deep. Space them six to twelve inches apart to allow room for growth. Water the soil lightly to keep it moist but not waterlogged. Keep the soil consistently moist until germination, usually within 7 to 14 days.

As they are fast-growing climbers, provide a trellis or support structure for them to climb.

How to Grow

Growing moon flowers is very easy given they are a voracious climbing vine. They can even be considered a weed in some areas. The vines grow under a variety of conditions, but we’ll discuss the optimal conditions needed to get the most flowers to bloom. 

Light

Plant in an area of the garden in full sun that receives at least six to eight hours of direct sunlight per day. These tropical flowers can be grown as a perennial in USDA zones 9-12. They will be grown as an annual in all other zones.

Water

Water moon flower vines in the early morning to allow the water to penetrate before the sun has a chance to evaporate it from the soil. They can survive in a variety of conditions and are relatively drought-tolerant, however, a deep watering one to two times per week will yield the most growth and more blooms. Water at the base of the vines with a soaker hose.

Since the vine is native to tropical climates, it prefers a fairly high humidity level. However, it will tolerate dry air as long as it is kept well watered. 

Soil

When planting moon flowers in your gardens, it is important to choose a site with loose, well-drained soil. If your native soil is not ideal, grow moon flowers in a container. This way, you can more easily control the soil conditions and make adjustments as needed. They can be grown in large containers, at least 12 inches deep, with plenty of drainage holes at the base. It can survive poor soil conditions and generally doesn’t need anything other than good drainage. They will not, however, tolerate acidic soil and do their best in neutral soil. 

Temperature

Moon flower vines can also be grown as far north as USDA zones 3-4 as long as they are grown during the warmest mid-summer months. That being said, the ideal outdoor temperatures for moon flowers are between 65-85°F (18-29°C). Once nighttime lows are reliably in the 60s (~16°C), that is a good time to direct sow your moon flower seed. In colder climates with shorter growing seasons, start seeds indoors six to eight weeks before transplanting them out. 

Fertilizing

Since moon flowers are a vigorous vine, it’s not absolutely necessary to fertilize them. However, if you choose to give it a boost, then there are a few things to note. Too much nitrogen fertilizer will boost the growth of the foliage but will limit the number of times moon flowers bloom. Half-strength high phosphorus fertilizer is the better choice to encourage more blooms. A liquid fertilizer applied in early summer will help boost your blooms for the remainder of the season. 

Maintenance

Moon flowers grow best on a support like a trellis, fence, or pergola. Plant them alongside the base of your support structure and as they grow tall enough, lean them over to your trellis and gently attach them with a twist tie or string. This will encourage them to reach in this direction. They will eventually grow tiny tendrils, grab onto the structure on their own, and continue to climb. 

When moon flowers are grown as a perennial, prune back to the ground in the autumn, and protect the roots with mulch over the winter. Your vine will come back to life in the spring. When grown as an annual, cut back the vines as they grow to control the spread or give an overall shape as needed and desired. 

Propagation

Although moon flowers are grown as an annual in most areas, they will readily self-seed and keep coming back year after year once they’ve established a patch in your gardens.

The white flowers only bloom once. After the flower has wilted, you will then see the seed pods begin to form in its place. Allow the seed pods to fully mature, and then remove them to dry. The following spring it will be time to plant your seeds!

Since moon flower seeds have such a thick seed coat, there are a few tricks to help aid in higher germination rates. Nick the outer layer of the seeds’ seed coat with a nail file and soak the seeds overnight in warm water. Choose your planting site and keep seeds evenly moist until they begin to sprout. 

Moonflower can also be propagated via cuttings, although this method is less reliable. Take a cutting of the vine just below the leaf node and remove foliage on the bottom two to three inches of the stem. Place the stem in a glass of water, and you should see roots begin to form in a few weeks. Once the roots have appeared, you may transplant them to your planting site outdoors, or they can even be grown indoors in a pot as long as they receive enough sunlight. 

Common Problems

As mentioned above, moon flower vines are relatively easy to grow and care for as long as they are provided with weekly deep waterings and well-draining soil. There are a few issues worth noting, however. 

Growing Problems

A lack of sunlight can drastically reduce the number of blooms and that’s the reason that we’re growing this vine in the first place! If you notice lackluster vine growth and no blooms, then consider the placement in your garden. They may need more sunlight! This is one vine that will not tolerate being planted in the ground in part shade. 

Pests

Moon flowers are a great way to attract nocturnal pollinators to your garden. However, that does come with a potential downside. They are known to attract hummingbird moths to your garden, which are beneficial pollinators. The hummingbird moth larval stage is a caterpillar referred to as a hornworm and has a very similar appearance to the dreaded tomato hornworm. However, they are not the same and do not cause the same destruction to your plants! Hornworms will chomp on foliage but are less destructive than tomato hornworms. 

That being said, moon flowers can also attract the five spotted hawk moth, the species whose eggs produce the dreaded tomato hornworm! It’s best to learn how to identify these moths and all stages of their life cycle so that you can appropriately dispose of potential pests as you come across them. I’ve found that checking the undersides of leaves regularly will help with pest management, especially if you begin to notice tiny holes in your leaves. Spraying your plants with BT spray can reduce the larval numbers.

Remove debris and leaf litter at the end of the season to avoid providing the caterpillars with the perfect overwintering site. Tomato hornworms will overwinter in their chrysalis stage. 

Diseases

Black rot is a bacterial disease that can affect moon flowers in hot and humid weather. It appears as yellowish-orange, V-shaped markings on the outer edges of the leaves and eventually causes the leaves to fall off. To prevent this disease, don’t crowd them together.

Disease problems are not frequent, and you can make sure they have good air circulation as a preventative measure. Make sure they are planted in your garden with adequate space, and selectively prune when needed. There are no treatments for black rot once the disease has occurred.

Frequently Asked Questions