Annual vines require less commitment and are more playful than perennial and woody vines, such as wisteria, clematis, and climbing hydrangea. They offer a chance to experiment. The small investment of a packet of seeds or a few transplants yields, in one season, an abundance of blooms.
Lisa Hilgenberg, a horticulturist at the Chicago Botanic Garden, calls annual vines "the divas of the garden—and they are sport-utility, too, because they are really beautiful and functional." Hilgenberg is in charge of the Regenstein Fruit and Vegetable Garden and is, naturally, partial to Malabar spinach, cucumbers, and other vines that offer an edible harvest. She has also grown many ornamental annual vines. "When we grow them, we want them to be plants with a 'wow' effect," she says.
All vines should be planted against a suitably sturdy trellis or tepee. Some need a little encouragement to get started and a bit of training as the season advances, but in a sunny spot, they grow and bloom without further pampering. Their bright flowers light up an arbor or pergola, and they're equally adept at covering an eyesore. "It's like painting a room," Hilgenberg says. "The reward far exceeds the effort."
"Annual vines are more popular than ever, because people are beginning to catch on that vertical gardening is really a good thing to do," says Renee Shepherd of Renee's Garden. "You can have more flowers or vegetables in less space."
There is perhaps no more dramatic vine than purple hyacinth bean, whose shiny purple pods gleam darkly from amidst a dense bower of dark green or nearly purple leaves. Hyacinth bean vines twine willingly and quickly up an arbor or race to cover a chain-link fence, growing up to 20 feet in the course of a season. At the Chicago Botanic Garden, gardeners grew hyacinth bean up an obelisk in a large pot, with ornamental millet and basil around the base, Hilgenberg says. She especially likes 'Ruby Moon', which has clusters of lilac flowers on long stalks. Plant seeds in full sun. Hyacinth bean is perennial in USDA Plant Hardiness Zone 10 and warmer; elsewhere, grow it as an annual.
More big vines: Spanish flag (Ipomoea lobata) and other vines in the morning glory family are easy to grow from seed. In hot-summer climates, they will twine 15 feet or more. Spanish flag bears showy clusters of small red-and-yellow flowers, starting in midsummer.