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.
Most annual vines thrive in hot summers. Sweet peas are the exception. "They need to be planted when you start your very first vegetables in the garden," Shepherd says. "They like cool weather, and they are brought into bloom by lengthening days." She recommends planting sweet pea seeds at the same time as parsley or lettuce. Be patient; the seeds may take several weeks to germinate. Sweet pea vines have little tendrils that grip a string, wire, or netting, and plants grow to about 6 feet tall in a sunny or partly shaded spot. The more the ruffled, fragrant flowers are cut for bouquets, the more lustily they bloom. In hot-summer climates, try starting sweet pea seeds indoors in late winter and moving the seedlings into the garden in early spring. Do not plant the seedlings deeper than they are growing in their pots.
More fragrant vines: Moonflower (Ipomoea alba) and cup-and-saucer vine or cathedral bells (Cobaea scandens) both have fragrant flowers and bloom in summer.
Indeterminate tomatoes are not technically vines, but the plants keep growing all summer long and are easiest to take care of when they have some support. Training tomatoes onto a trellis with twine also makes them more presentable in a sunny spot on a patio. Cherry types are perhaps the best choice for a trellis; they produce a prolific crop from early summer through frost, and their bright fruits are both decorative and delicious. Try growing two or more varieties, such as 'Sun Gold' and 'Black Cherry', on the same trellis for a festive combination of colors and flavors.
More crops that climb: Malabar spinach with red stems (Basella alba 'Rubra') "is absolutely gorgeous," says Hilgenberg. Its leaves are more substantial than true spinach leaves, and they taste best cooked, rather than as salad greens. Cucumbers, miniature pumpkins, and pole beans all will cover a trellis in a sunny garden. Shepherd likes to plant a combination of colorful beans for their decorative effect.
Morning glories are early risers, unfurling their magnificent trumpets with the first light. Each flower lasts only a day, but the vines produce many pink, blue, white, or fancy bicolor flowers daily. Plant seeds when night temperatures are consistently above 50°F, and thin them according to package directions. Three vines on a trellis or tepee will be plenty. They grow fast, twine lustily, and bloom until frost.
Morning glories grow from hard seeds; many gardeners recommend nicking the seeds with a file or soaking them overnight to encourage germination (use this trick with sweet peas, too). Soak for a maximum of 8 hours, and nick them if you like—but waiting until warm weather arrives is more important than either, Shepherd says.
Alternative for night owls: Moonflowers are comparable to morning glories in every way, except they open at dusk. If you time it right, you can watch the fragrant white blooms open before your eyes. They flourish in areas with long, hot summers.
Hummingbirds are attracted to many flowering vines, but they seem just the right scale for cypress vine, which is covered with tiny white, bright red, or pink flowers in mid to late summer. Red flowers are the most common, but some seed companies sell packets of mixed colors. Cypress vine will twine up strings, cover a trellis, or scramble over shrubs; give it room to grow. It blooms best in areas with hot summers (and can self-sow invasively). The wispy, feathery foliage looks delicate, like tiny palm fronds, but the plants are tremendously heat- and drought-tolerant.
More vines for hummingbirds: Cypress vine is sometimes confused with cardinal climber (Ipomoea x multifida), which also has small red flowers. Cathedral bells, hyacinth bean, and morning glories attract hummingbirds, too. Shepherd's favorite hummingbird vine is scarlet runner bean. It does not bloom in the heat of summer, but it's pretty in fall or spring, and the beans are edible.
Gloriosa superba 'Rothschildiana'
Gloriosa lilies steal the show in a small space. These well-mannered scramblers grow to only 6 feet tall and are a great choice for a trellis or obelisk in a pot. Gloriosa lilies are members of the lily family but grow from tubers (buy them in spring), not bulbs. The vines have glossy leaves with curious corkscrew tendrils at the tips, reaching for something to cling to. The flamboyant yellow-and-red flowers have slightly twisting, reflexed petals that make the blooms look like flickering flames.
Gloriosa lilies should be planted in well-drained soil in full sun. Plant three tubers on an obelisk for a great show. They are hardy to Zone 8; in warm climates, they will die to the ground in fall, and come back to bloom reliably for several years.
This pretty vine is not related to the perennial black-eyed Susan (Rudbeckia hirta), but the two flowers share a color scheme. The old-fashioned vine has glowing, golden-orange flowers with dark centers; it blooms profusely through the summer. It is very easy to grow from seed, but transplants have become widely available in recent years—along with new, early-blooming cultivars in orange, pink, or yellow. 'Blushing Susie' is one of Hilgenberg's favorites.
It can be difficult to find an annual vine that performs well in light shade, but black-eyed Susan vine doesn't mind dappled light. The young plants need a little encouragement to reach up to their supports. Once they get started, they twine nimbly around a wire trellis (or a tomato cage). Vines grow 6 to 8 feet. Black-eyed Susan vine is handsome in hanging baskets, which can be overwintered in a frost-free basement or garage. Or take cuttings, root them in potting soil, and plant in the garden again next spring.
Mandevilla is the mailbox vine of the moment. This twining, woody tropical vine is sold at garden shops in pots and is grown as an annual. The lush, cheerful flowers are up to 4 inches across. They're big enough make an impression at the curb, even if the traffic is going by at 35 miles per hour, but the vines are well mannered and do not threaten to engulf the mail carrier. Compact new cultivars in the Vogue series are pretty in hanging baskets.
Mandevilla vines may grow to 20 feet or more in southern Florida, where they are winter-hardy, but they remain smaller in more temperate areas or when grown in pots. Gardeners at the Missouri Botanic Garden in St. Louis note that container-grown mandevillas climb 3 to 5 feet. At the end of the gardening season, cut them back and move the plants to a sunny room indoors; return them to the garden after the danger of frost is past in spring.
Illustrations: Elara Tanguy