How to Get Moonflowers to Bloom: 7 Growing Tips
Moonflowers are close relatives of morning glory vines with pure-white blooms and heart-shaped leaves. The last thing you want to see is your vines full of leaves and no flowers! Seasoned grower Jerad Bryant shares seven tips to get your lackluster vines from bare to readily blooming.
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Though moonflower can refer to many different plants, it most often refers to the morning glory relative Ipomoea alba. The Florida native vine grows perennially in tropical and subtropical climates, and it performs well as an annual in regions with winter frost.
The moonflower blooms sweet-smelling blossoms from summer through fall until frosty weather arrives. If your vine is lackluster or bloomless, it’s a good idea to check its environment and ensure it’s conducive to healthy growth.
It also blooms at night! The name hints at its nocturnal nature; you’ll notice white buds opening before your eyes as the afternoon fades into the evening. Nocturnal moths like the hummingbird and sphinx moths pollinate their flowers under the cover of the moon.
A bloomless vine is not a pleasant sight. Try these seven tips to get moonflower buds to bloom along all its twining stems.
Start Seeds Ahead of Time
Unlike spring bloomers, moonflower vines flower in late summer and fall, and they need plenty of time to grow in order to bloom. Gardens with short growing seasons may not have enough time for the plants to mature and form flower buds. If your growing season is less than three to four months long, it’s best to start seeds indoors for transplanting after the last frost date.
Sow moonflower seeds in biodegradable pots that allow the roots to grow without disturbance. They’re sensitive to transplanting and prefer to stay in one spot. Biodegradable pots break down after transplanting, allowing the roots to spread from the pots into the garden.
Plant the seeds ½ inch deep in the pots and water them well. Maintain consistently moist soil while providing bright light from a window or grow lights. The seedlings will emerge 10 to 20 days after planting. Keep them moist, well-lit, and free from hot or cold drafts until a week or two after your region’s last average frost date.
Transplant Seedlings
Moonflowers require warm soils to get them bloom. It’s better to wait to plant or transplant them than to start early. Once the ground is warm and night temperatures are above 50°F (10°C), begin transplanting seedlings or planting seeds. Optimal soil temperatures are between 70 and 80°F (21-27°C).
Start by preparing the site for planting. For seedlings, dig holes as deep and twice as wide as the biodegradable pots. Put the moonflowers in the hole with their paper pots, and backfill the soil to cover the hole. Water the site well, and fill the holes again if any of them sink.
For seeds, plant them ½ inch deep in the ground. Sow four seeds every six inches, and thin them after sprouting to a single seedling every six inches. You may space them further apart if you’d like, though they benefit from at least six inches of space.
Offer Support
Vines like to grow up! They rely on trees, shrubs, and structures to reach higher into the sky, as they lack woody stems to keep them upright. Grant them a supporting structure like a trellis, arbor, or fence to help them perform in your home garden.
Without support, the plants act as groundcovers along the dirt. They may not receive the sunlight and airflow necessary for ample blossoms at the end of summer. Ensure your seedlings have support when they’re young so they can quickly reach towering heights.
With ample support, some vines can reach 10 to 30 feet long! Fences are ideal supports, as are patios, porches, and open wooden structures. You can line an arbor with moonflowers for a fragrant archway, or create a living screen with upright supports and ample vines.
Provide Plenty of Heat
These vining spreaders need lots of heat to do well. A part of proper heat is decent exposure; these perennials thrive with full sun. Grant them six to eight hours of daily direct sunlight during the growing season, since they’ll have fewer blooms and leggy growth in the shade than under the sun.
In regions with cool summers, a head start on the growing season is crucial in giving these plants enough time to form flowers. Plant them in a location with a southern exposure for the best results. Southern exposures capture the most sun throughout the day.
These plants do well in containers, raised beds, and hanging baskets. Aboveground planters heat up quicker than in-ground beds, allowing you to plant seeds or seedlings in early spring. So long as the ground is warm, the plants will sprout ample roots, shoots, and buds.
Water Regularly
Though moonflowers are drought-tolerant, they grow their best with consistent moisture. Moist soil promotes healthy root growth in all directions. The more roots your plants have, the more flowers they’ll be able to support during the blooming period.
Moist soil is best, and soggy soil is deadly! Avoid overwatering your plants by checking how wet the dirt is before watering. You want the ground to be as moist as a wrung-out sponge. Pick up a clump of it and squeeze—some water should fall out when you press on the dirt.
Proper soil helps moderate moisture levels. Grow moonflowers in well-drained, fertile soil with plenty of air pockets. Clay, loamy, or sandy soils work well, as these perennials are adaptive and vigorous. You’ll have to water less often with clay and more often with sand, while loam is a perfect middle ground between the two.
Add Compost or Fertilizer
Extra nutrients can help poor-growing vines grow ample new shoots and buds. Compost is an ideal mulch to add around the root zone; it adds nutrients, microbes, and structure to the soil. It’s a natural amendment made from carbon and nitrogen-rich waste materials.
Make compost yourself in the backyard, or find a mix you trust from local nurseries and garden centers. Homemade compost contains plenty of worms that help improve soil fertility and structure. Spread a layer two to three inches thick over your plants’ roots, leaving some space between the aboveground stems and the compost.
Without compost, organic fertilizer works well as a substitute. It doesn’t provide structural support for the soil, though it does feed it with plenty of nutrients. Use a low-nitrogen fertilizer to avoid ample leafy growth at the expense of blooms. Find one with some nitrogen and plenty of phosphorus and potassium.
Wait for the Right Season
So long as you provide your plants with all the above conditions, they’ll bloom when the time is right. You’ll have to care for their leafy stems until summer’s end when the days begin shortening and the nights start lengthening. Stay up at night to watch the buds open under the moonlight, and gaze over the dozens of moths that flock to the fragrant flowers.
As the temperatures cool in the fall, the blooms fade before turning into seed pods. Collect the seeds to have a supply for next spring when the growing season returns. Store ripe seeds in a cool, dark location inside a closed container.
If you can’t get your moonflowers to bud or bloom in late summer or autumn, they may not have received what they need during the growing season. Proper care during spring and early summer is key to a successful flowering period.
Don’t fret—you can always try again next year if it doesn’t work out this time. Mark down what works and what doesn’t, and modify your growing process next year to promote ample moonflower blossoms.
