Among the few common garden plants that bloom at night, moonflowers are a sought-after annual vine. Moonflowers are easy to care for, requiring little feeding, and the vines will grow quite large, making them ideal for covering walls.
Soil Conditions
Good moonflower care starts with well-drained, fertile soil. Amend the soil by mixing in a few cups of sand if there is any doubt about how well the soil drains. Like related morning glories, moonflowers don't thrive in boggy soil.
Watering and Feeding
Water plants weekly, along with all other annuals in the garden. Water twice if there has been no rain in a given week. Moonflowers should be fed a few times with regular garden fertilizer as the seedlings emerge from the ground. They can then be largely left alone until late summer, when they begin to bloom in temperate climates. Feed them a few times (once every other week) in late summer through the first hard frost to produce the largest and healthiest blooms.
Deadheading
As with all annuals, deadheading (removing spent flowers) will prolong the time the plants bloom, and make the flowers healthier and larger. Simply pull withered flowers gently off the plant. If they don't come off easily, wait a few days and try removing again--don't pull too hard.
