The moonflower (Ipomoea alba) is a perennial, twining vine that is native to the American tropics. It grows fast enough to be treated as an annual in cooler climates. Moonflowers are related to the morning glory and produce spectacular white flowers that open in early evening and close at dawn. The white flowers attract night-flying moths that the moonflower needs for pollination.
Moonflower vines have rich green, heart-shaped leaves that are 4 to 6 inches long. Each stem carries several 4-inch-long buds. The moonflower produces its 5- to 6-inch-wide blossoms all summer long. The aromatic blossoms come in the form of alabaster-white, fluted funnels. The moonflower vines will climb until it frosts. They usually grow about 15 feet long.
When the flowers shrivel and die in the morning, they leave behind rough husks that are filled with white seeds that resemble dried garbanzo beans.
In areas with mild temperatures and long growing seasons, plant moonflowers outdoors after the last frost. Chip or file the hard coverings of moonflower seeds, then soak them in water 24 hours before planting in pots of peat. The seeds will germinate in a week or so. Quick-growing varieties of moonflowers will immediately twine around each other or climb on anything at hand. Insert twigs in the pot to give them something to climb; transplant them when the spring weather warms up. Organic compost will make the seedlings grow more vigorously. Moonflowers can also be propagated by rooting their runners.
Climate and Soil
In most growing zones in the United States, moonflowers can only be grown as annuals. They grow extremely rapidly in hot weather. Plant moonflowers in moderately rich, well-drained soil where they get plenty of sun. If the soil is too rich, the plant will produce lots of foliage but few blossoms. Do not let the soil get soggy by overwatering.
Moonflowers are ordinarily planted along an arbor, gazebo, fence, wall or terrace that will give it support. The moonflower grows rapidly and is sometimes used to screen eyesores. They can be grown in containers. In areas that are free of frost, the aggressive moonflower vines will drape a forest canopy in huge green curtains. In some areas, moonflowers are considered invasive.