Creatures of the Night

Fragrant moonflowers open at night, but stay open till the next morning. Photo by Karen Dorsett

A few weeks ago, my sister Kim called to tell me about a startling experience with a bat or bird fluttering around their moonvine. I haven’t grown moonvine or moonflower (Ipomoea alba) since the shade shelter over my patio collapsed, so I was delighted to hear about one of my favorite plants.

I saw moonflowers for the first time in the pages of Peter Loewer’s Bringing the Outdoors In: How to Do Wonders with Vines, Wildflowers, Ferns, Mosses, Bulbs, Cacti, and Dozens of Other Plants Most People Overlook (Contemporary Books, 1974). Loewer did the illustrations too and they are wonderful. Inspired, I planted moonflowers (or moonvines) in my garden. The vines climbed the shade shelter, growing larger and larger leaves. They seemed to enjoy the hot summer, but alas, they produced no blooms. Concluding that I had planted too late in spring, I tried again the next season. Again, huge healthy vines shot up, providing shade but no blooms. 

Daytime camouflage of
Pink-spotted Hawkmoth. Photo by cwphobia

Then one fall night I happened to walk out in the backyard and behold! A huge white bloom, every bit of 6 inches in diameter (15.24 cm)! I noted the fragrance too, and realized that it was familiar. My vines must have bloomed the previous season, but at the top of the shade shelter where I couldn’t see the flowers. About then something fluttered past my ear—then another! I was about to beat a rapid retreat into the house, but there was just enough light for me to see that the winged monsters were moths. Almost as big as the flower, the moths (possibly Pink-spotted Hawkmoth) appeared to blunder into the delicate white bloom and then bounce away. 

Kim got this shot with her phone on Oct. 14

Kim told me that when she transplanted the vine into her garden last spring, she thought, “Well, I’ll never see you again.” But the tiny vine plunged through the lush growth and found itself in moonvine heaven. It leaped over the roses and laughed at the trellis, but it refused to set buds till September. Reassured that bats were not invading the patio, the spectacle of opening buds began to attract the attention of human neighbors too. Kim told me that when the weather is warm, “The buds pop open like a firecracker.” It it’s cooler, they unfurl more slowly. In very cool weather, the buds wither away without opening. Kim and Steve have hosted friends for moonflower-gazing parties almost nightly. Sounds very Zen, doesn’t it? Except I think they served wine, not tea. On October 10, following daytime temperatures in the mid-80s, 23 blooms opened! That night, the thermometer dipped to 42°F, and the next night, in spite of another unseasonably warm day, only 7 opened. This just in: 3 are open tonight.

I’ve read discussions on when to plant, whether or not to fertilize, and lots of other tips to encourage moonflowers to bloom earlier. Here in St. Louis, Missouri, our average date of first frost is between Oct. 11-20, so a tender vine that doesn’t get going till mid-September may not merit space in the garden. Like another favorite of mine, Mexican sage, the blooms depend on day length, not on any factor that gardeners can control. In its native South and Central America, apparently it doesn’t pay to bloom when days are long. For gardeners though, what could be better than a plant that blooms when nights are long?