Moonflower Vine Care & Growth Tips

Plant background

The ipomoea (genus) alba (species) plant is generally referred to as a moonflower vine. It was formerly classified as genus Calonyction and is a type of night-blooming morning glory. Morning glory is the common name for the genus ipomoea. If a moonflower vine is planted in the ground, it can get up to 15 feet tall or long. It also has quite the spread—mine has taken over a 6-foot trellis.

The plant gets its common name from the fact that it blooms primarily at night. It has evolved to do this because night-flying insects are generally the primary pollinators. You’ll see the buds developing over a series of days.

When they are ready to emerge, the billowy white flower will open quickly around dusk and last all night. You can usually catch them fully open in the morning, too. Once the sun rises, the flowers will close up.

The foliage on the plant is a lush medium green with two types of leaves: a whole, heart-shaped leaf, or a three-lobed leaf. The foliage on the plant climbs and vines beautifully and readily. It will grab onto almost anything without training.

Planting location

You can plant your moonflower vine anywhere that gets plenty of direct sunlight. You just want to make sure you have something for the vine to climb. And this plant grows FAST!

I have used twine tied to two nails in the past, and that worked great. This year, I made a huge DIY wire trellis using concrete remesh. This was a perfect trellis solution for such a prolific vine. I’m planning to get a few more wire panels to grow a couple next year!

Growing in pots

Moonflower vine can be grown in pots. I grew my moonflower vines in pots until we moved to our current home where I have more space. It will likely not grow to be as large as if you’d planted it in the ground, though.

Despite that, it can still grow to pretty impressive heights. In our old house, we had a second-story deck that I liked growing moonflower vine up. Then I’d string twine across the bottom of the deck to let it climb all over that, too (see pic below).

In a pot, you’ll want to make sure you give it plenty of water. It will wilt much faster in the heat because the water will evaporate from the potted soil faster.

You might also notice the plant dropping its bottom-most leaves toward the end of the season. I always chalked this up to the plant running out of room in the pot and needed to conserve energy, directing its efforts toward the new growth and killing off the old.

Encouraging blooming

I have grown these plants in two different homes with different soil compositions, as well as in pots. Because of that, I believe that they are an easy vine to grow! And they have flowered like crazy.

However, you can encouraging blooming on your moonflower vine by making sure it gets enough light. Mine gets direct sun nearly all day long. Give it plenty of water, too—even in the ground, it will wilt with extreme heat.

I also generally give my moonflower vine a balanced garden fertilizer once a month in May, June, and July. I’ve never done a side-by-side to see if it really helps, but it certainly hasn’t hurt!

Deadheading

You should deadhead dying moonflowers. You can encourage more flowering by picking off the spent blooms (aka dead heading). However, I’ll say that I rarely deadhead mine. I usually let the flowers fall off by themselves.

And despite not deadheading my plants, they have bloomed prolifically! I usually have 5 to 10 blooms in various stages at any time, which is awesome.

Hardiness

Where I live, moonflower vines are an annual flower. That’s because it gets very cold here in Maryland. They are officially designated as perennials, meaning they come back year after year, in USDA growing zones 10, 11, and 12.

However, I would not be surprised to see the moonflower vine as a perennial in zone 9. It seems that our ever-evolving weather is leading to some plants surviving the winter in areas of our country where they didn’t previously.

In some warmer areas of the United States (including Hawaii), it can be invasive. Whenever you plant something in the ground, I recommend looking into your grow zone and researching invasive plants. Usually your local Master Gardener chapter or a local nursery can answer any questions you have!

Toxicity

According to the ASPCA, ipomoea plants have seeds that can have a hallucinogenic affect if ingested in large quantities. The plants also contain indole alkaloids (Lysergic acid, lysergamide, elymoclavine and chanoclavine), which can be toxic to humans and animals and cause vomiting.

Despite the fact that it isn’t a great idea to ingest any part of ipomoea plants, moonflowers are not poisonous to the touch. You can safely plant moonflower vines, deadhead flowers, prune the plant, collect seeds, and cut off vines.

However, I always recommend wearing sturdy gardening gloves. Especially because I’ve found that the stems can get a tiny bit prickly as the plant matures.

Saving seeds

You can harvest seeds from your moonflower vine to grow next year, too. They are easy to collect, but your plant needs to develop seed pods first. Seed pods are green, purple, or brown and are shaped like teardrops.

However, you want to wait until the pod browns and gets crispy. If you harvest the seeds before then, they won’t be mature enough. If you wait too long, the husk might crack on its own and drop the seeds. To avoid this, you can remove the pod once it is completely brown but before it has split. This might take some monitoring over a few days.

Spread the seeds out on a paper towel in a dry spot and let them dry further for a few days. If they have even a bit of moisture in them, they will mold in storage. Once you are sure they are completely dry, store them in an airtight container or a paper bag for the winter.

Below are a few photos showing this process. The first photo is how my plant looked after two light frosts. Dying off, but definitely not dead yet. I checked the plant over and found a few seed pods that were ready.

The purple seed pods are NOT ready to harvest. The dried, brown and crunchy pods are ready to harvest (see photos below). I’ve harvested pods with one, two, three, and even four seeds. I laid the seeds out on a paper towel for 24 hours and then stored them in a baggie for the winter.

Growing from seed

Once spring is on the horizon, it’s time to start your plants. You can start the seeds indoors 1 to 2 months before planting time. (Remember, planting time is after your last frost date since this one isn’t frost hardy.)

To grow a moonflower vine from seed, knick each seed with a sharp knife to break the outer layer. Then soak them overnight in water. Plant each individually in a rich seed-starting soil. The best option is to use something you can transplant directly in the ground like a biodegradable pot or eggshell. Moonflower vines don’t like their roots handled, and baby plants are especially finicky.

Once the seeds have sprouted, you can begin to add more sunlight to the routine. If you transfer the plants right outside into the sunlight, it can shock the plant. Just setting a seedling tray out in the sun for a bit each day can help!

You can plant the baby moonflower vines in pots or in the ground once there is no danger of frost and the temperatures reach into the 60s or higher Fahrenheit during the day.

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