Moonflowers open in the evening about dusk and stay open until the first light of morning so they can be pollinated by night-flying moths. Like most many moth-pollinated flowers, the moonflower is white with large trumpet shaped flowers, but there are also pink ones. They have a beautiful twining vine that grows fast in really hot weather. They are a close relative to the morning glory, which open in the morning so bees and other insects can pollinate it during the day. Moonflowers only bloom once before they fade, but the plant produces many new blooms during its growing season. It has a heavenly fragrance that permeates the whole garden. They need to be planted in full sun and are an annual in our zone 5, blooming mid to late summer. They are very easy to grow with very little care, but you want to have a large space for them because they grow up to five feet tall and four feet wide and can be invasive. A trellis or along a fence is a good place to plant them. Warning: they can be toxic to domestic animals and children if eaten, but just touching the plant is not harmful.
The seeds are easy to harvest for the next years planting; just leave some blooms on the vine after they fade. The wilted flowers will drop off, revealing seedpods that hide at the base of the flowers or you can snip the wilted flowers from the vines with a pair of scissors. Then drop the pods into a brown paper sack and wait for them to turn brown and dry. Place the sack in a cool, dry place for the pods to finish drying. The pods can take up to a month or longer to dry. When the seeds have completely dried, open the pods and the seeds will drop out. Place the seeds in a paper envelope, date and label them.
Before planting, nick the seeds slightly, and soak them for eight hours. This will enable faster germination. You can plant them indoors or directly in the ground after the weather warms up in the spring. They do need some watering to get them started.
Moonflowers can be found as an established plant in garden centers also.