Gardeners have long had a love affair with flowering annual vines - fragrant night-blooming moonflower (Ipomoea alba), love-in-a-puff (Cardiospermum halicacabum) with its translucent Chinese lanterns, and the soft nostalgic pinks and lavenders of climbing sweet peas (Lathyrus odoratus). They're both beautiful and useful. Flowering annual vines can turn an ugly chain-link fence into a gorgeous garden wall, obscure a propane tank or create a blooming bower.
"In Victorian times, people often grew annual vines up a trellis by the porch so it would be shady and private," notes Marilyn Barlow, owner of Select Seeds in Union, Conn.
Annual vines grow fast - depending on the plant, as much as 30 feet in a season - producing a big effect in a short time, which is what makes them great summer cover. But they can also wonderfully enhance the garden - frothing over a garden fence, adding height to a perennial border, blanketing a child's tepee, or even transforming a bare apartment balcony into a tropical hideaway.
"Because their root systems are limited, most annual vines can be grown in pots," says Jackie Carroll, editor of the Internet garden site www.gardenguides.com.
And because they die each fall, annual vines won't take over the way some perennial vines, like English ivy, do.
Annual flowering vines, many of which are tropical natives, come in a wide selection of bloom colors and configurations. Delicate heirloom cypress vine (Ipomoea quamoclit) has little white stars among filigreed leaves while climbing 'Jewel of Africa' nasturtium sports lavish fiesta-colored edible flowers in wads of foliage from mid-summer to frost. There is magnificent cathedral bell (Cobaea scandens), also known as cup and saucer vine, whose ruffled demitasse-sized blooms come in royal purple or lime white and produce seedpods that look like Russian bishops' hats. There are 'Painted Lady' and 'Scarlet Runner' beans (Phaseolus coccineus), beautiful heirlooms that draw hummingbirds and butterflies, while hyacinth bean (Dolichos lablab) has large, wine-veined leaves and pale mauve flowers that eventually produce thick clusters of shiny burgundy pods.
"Mandevilla, which has a big glowing pink flower and leathery leaf, is very showy," says Barlow. "It's a heat lover, is lightly fragrant and is fairly quick to bloom, especially if it starts as a plant rather than being put in as a seed. And it does really well in a pot on a deck."
There is creeping gloxinia (Asarina), a snapdragon relative that grows 6 to 9 feet. Asarina scandens is covered with violet-purple trumpet-shaped blooms and A. wislizensis 'Red Dragon' has soft crimson blossoms with serrated dragon-toothed leaves. Black-eyed Susan vine (Thunbergia alata), also known as clock vine, is available in stark white with purple-black eyes, pale yellow, butter, sunset rusts and apricots, and even Copenhagen blue with saffron eyes. The delicate blossoms of canary creeper (Tropaeolum peregrinum) look like tiny yellow cockatoos in flight. And of course, there are morning glories (Ipomoea), the classic Victorian cottage vine. While some ipomoeas, such as moonflower, need to be carefully replanted annually, others reseed prolifically each year.
"The purpurea types like 'Grandpa Ott's' morning glory, hearts and honey vine [Ipomoea luteola], and cypress vine reseed readily," notes Barlow, "though it's pretty easy to pull out the volunteers you don't want."
One eye-popping annual flowering vine is passionflower (Passiflora) - among them our native maypops (P. incarnata) - whose blooms look like sea anemones with whirligigs on their heads.
While most annual vines prefer full sun, several - such as black-eyed Susan vine, cypress vine and cardinal climber (Ipomoea x multifida) - will bloom (though less profusely) in partial shade. All need warm, settled weather. Starting seeds indoors or buying plants gives you a jump on bloom time.
Provide support - anything from a wrought iron arbor to rustic tepee. In the beginning of growth, gently train the vine along supports to prevent crowding. Also some, like Mexican flame vine (Senecio confusus), bloom better when pinched back early on.
"Shorten it by 3-4 inches at least once, maybe twice before flowering," says Barlow, "until you've got a bushy plant going. Then let it flower and you'll have lots of blooms."
"To keep black-eyed Susan vine fat and full, during early stages give it a little haircut around the edges and the base will keep sending out shoots," says Pat Waldt, grower at Radebaugh Florist in Towson.
In general, annual flowering vines benefit from weekly feeding.
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