The evocative name moonflower suggests warm summer nights and moonlit blooms draping over a trellis, but not all plants commonly called moonflower are vines, although they do all bloom at night.
The two plants most commonly considered moonflowers are white morning glory (Ipomoea alba) and moonflower datura (Datura stramonium). The flowers of white morning glory are always white, but the moonflower datura flowers vary in color.
White Morning Glory Moonflower
White morning glory, or Ipomoea alba, is a perennial vine plant that is cultivated as an annual in most climates, growing in USDA hardiness zones 10 to 12. It grows best in full sun and requires well-draining soil, as do most plants.
Moonflower seeds are poisonous, so monitor the area if small children or pets are nearby.
It has white flowers, which is not surprising given that “alba” is in its name. Its flowers have a sweet fragrance and bloom throughout the growing season.
It is also commonly known as moon vine or tropical white morning glory. Its 15-foot climbing vines sport heart-shaped leaves with flowers that are night-blooming, making it a prized climber in any night garden. It needs a trellis or other support for these long, twining vines.
This moonflower plant, Datura stramonium, is not a vine but instead grows in a bush form, reaching about 3 to 4 feet tall and wide.
There are other Datura species, but this species is the only one referred to as moonflower. It has several other common names as well, including Jimsonweed, sacred datura, devil’s trumpet and Jamestown weed. Its trumpet-shaped flowers face upward, unlike species of the Brugmansia genus, with which it is frequently confused, which has pendulous flowers.
This plant is considered invasive in some states, so check with your local university extension office before planting it.
Growing in zones 6 to 9, this plant is far more hardy than Ipomoea alba and is commonly considered a weed for its invasive characteristics. However, it has excellent ornamental value in certain areas. Grow moonflower in full sun and well-draining soil. It can grow in partial shade, but its flowers will not be as numerous.
The colors of the flowers of this moonflower plant range from white to lavender to a pinkish-purple. As they open, they resemble a cigar unfurling. The blooms give way to seed pods with sharp spines. If these are left on the plant, they burst, and the plant easily self-seeds, hence its invasive potential.
I garden in the Pacific North west, previously Hawaii where I had an avocado orchard. I have a Master Gardeners certificate here in Eugene, Oregon.