Moonflower Plant Profile

Moonflower (Ipomoea alba)

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Moonflower is a tender perennial vine that can add incredible beauty and powerful fragrance to a night garden. Grown as annuals in many regions, these plants have large, beautiful, heart-shaped leaves growing on huge, robust vines that need a large trellis to support them. The iridescent white, trumpet-shaped flowers are around 6 inches long and 3 to 6 inches wide. These spectacular flowers unfurl from cone-shaped buds as the sun goes down and on some cloudy days. Moonflower plants are perfect to grow in an outdoor eating area or near a bedroom window, where their fragrance can sweeten the night air.

Botanical Name Ipomoea alba (formerly Calonyction aculeatum)
Common Name Moonflower, tropical white morning-glory, moon vine, evening glory
Plant Type Perennial flowering vine (grown as annual in cooler climates)
Mature Size 8 to 10 feet
Sun Exposure Full sun
Soil Type Moist, well-drained soil
Soil pH 6.0  to 8.0 
Bloom Time Summer to fall
Flower Color White; sometimes purple
Hardiness Zones 10 to 12; grown as an annual elsewhere
Native Area Tropical and subtropical South America, Central America, Florida

How to Grow Moonflower

Plant moonflower in moist, well-drained soil, and make sure to give it a trellis or other structure to climb. Try growing moonflowers with related species of morning glories that bloom during the day for a spectacular flowering display. Day-blooming morning glories will flower when the sun is out, and the moonflowers will take over as the sun goes down.

Moonflower is an eager self-seeder, so if you don't want it to return next year, pick off the spent flowers so that they don't form seed pods.

This vine can become an invasive plant in certain areas of the country where it is a perennial vine. This includes Florida, Hawaii, and other southern areas, where most species of Ipomoea are prohibited "noxious weeds." If you live in a warm climate, check with local agencies before planting moonflower.

Light

Grow in full sun for the best blooms. Moonflowers readily adapt to part shade conditions.

Soil

The moonflower is tolerant of a wide variety of soil types and acidity levels, but it does best in soil is nutrient-rich loam. It prefers well-drain soil and does quite well in poor, dry soil.

Water

Young plants should be watered regularly until they are established. Moonflower has average water needs and you may water it about 1 inch per week, especially during hot periods. It likes moist soil that isn't soggy. It will tolerate short dry periods but will be killed by a long dry spell without water.

Temperature and Humidity

Growing moonflowers isn't hard in a warm climate since they are tropical white morning glories that can take the heat and high humidity. Moonflowers are perennial natives to Florida, Louisiana, Texas, Puerto Rico, and the Virgin Islands, and have been thriving in Hawaii, where they are an introduced species. But in cooler climates, they are grown as annuals and planted outside when the temperature is consistently 60 to 70 degrees Fahrenheit.

Fertilizer

Fertilize regularly with half-strength high-phosphorus fertilizer during the blooming season. Avoid high-nitrogen fertilizer as it can promote foliage at the expense of blooms.

Varieties of Moonflower

In general, moonflower seeds are sold without a variety designation, often as an heirloom plant.

Propagating Moon Flower

If you live in a colder climate, start indoor seeds early. If you have harvested seeds from existing plants, make sure they have fully dried on the vine before you collect them.

  1. Plant seeds indoors under lights, approximately four weeks before nighttime temperatures are consistently higher than 50 degrees Fahrenheit. The plants take a while to set flowers so make sure to start them early enough.
  2. Soak seeds in warm water for four to eight hours before you plant them. This will help with the germination rate.
  3. Fill plantable seedling pots (peat pots or cow pots work well) with a potting soil that is fast-draining but that doesn't have too much fertilizer. Too much fertilizer creates plants with lots of leaves but few flowers. Moonflowers don't like to have their roots disturbed, so it's better to plant in pots that can be buried directly.
  4. Sow the seeds in the pots, covering them with 1/4 inch of potting soil. Place the pots in a warm, sunny indoor place and keep the soil moist until seedlings appear.
  5. Once nighttime temperatures have reached 50 degrees, plant the seedlings—still in their peat pots—into the garden or into larger containers.

Toxicity of Moonflower

There is general confusion over toxicity because the common name "moonflower" can refer to different species. Ipomoea alba ingestion has been studied in mice and has been shown to have some mildly toxic effects. It is probably still wise to avoid ingesting it and exercise caution for children and pets who might do so. It is listed by Poison Control agencies as having only effects on the skin, such as a rash.

Meanwhile, Datura inoxia, which is also sometimes called moonflower, is very toxic. The Datura plant is related to Jimson weed and all parts of the plant contain high amounts of toxic atropine, scopolamine, and hyoscyamine. The symptoms can include delirium, bizarre behavior, fast heart rate, high body temperature, dilated pupils, and amnesia. It is necessary to protect anyone from ingesting any part of the Datura plant, including seeds and flowers.