Colourful annual climbers
Whether it’s a wall, a fence, trellis, or side of a building, most landscapes have a site that is perfect for colorful climbing vines. Some of the best choices are annuals such as morning glories, sweet peas, and nasturtium.
The morning glory (Ipomoea tricolor) is one of the most popular annual vines, with many colors from blue, purple, red to white. Interestingly, it is closely related to the sweet potato (Ipomoea), both the ornamental and edible food crop varieties. Twining around supports, it usually reaches 10 to 15 feet. Beware of placement, as it tends to self-seed prolifically.
Related to the morning glory are two red species, the red morning glory (I. coccinea) and the cypress vine (I. quamoclit). The latter has attractive, finely divided leaves. Any of the morning glories and relatives are attractive on fences, or climbing strings around posts such as of mailboxes.
Another popular annual vine is of course the sweet pea (Lathyrus odoratus). Known for its many colors and pleasant fragrance, the sweet pea can grow to 10 feet given cool temperatures and plenty of light. Once flowering, remove spent flowers and fruits to promote continued blooms. Sweet peas are wonderful on trellises, and under windows through which their fragrance can be appreciated.
There are many more annual vines to choose from. The black-eyed Susan vine (Thunbergia alata) has dark centered flowers, and although traditionally golden can now be found in various shades of orange, yellow, and even white. This less vigorous vine is seen on short trellises, and hanging. The cup and saucer vine (Cobaea scandens) has greenish cup-shaped flowers becoming more violet with age, surrounded by sepals for the saucer appearance. Flowers on this plant are large, the vines quite vigorous reaching 15 to 20 feet. This plant makes a quick screen.
Nasturtium (Tropaeolum majus) has unique clawed flowers with a long spur, and comes in colors such as red, orange, yellow, or peach. Usually they are bought as a mix of colors. I’ve found with some cultivars (cultivated varieties) and some years the flowers hide beneath the rounded leaves on long stalks. Watch when buying them, as many selections make mounded plants rather than five-foot vines. Nasturtiums perhaps look best trailing over edges of containers, walls, or raised beds.
There are two annual beans that make interesting and colorful vines. The hyacinth bean (Lablab purpureus) was formerly in a different genus (Dolichos), but whatever the name remains a vigorous vine reaching 10 to 20 feet. The fragrant, purple, bean-like flowers result in attractive purple beans which are edible and popular in the tropics. The scarlet runner bean (Phaseolus coccineus) resembles the typical garden pole beans, only the flowers are a bright eye-catching scarlet. Either bean looks good on trellises or for quick screening.
Being annuals, most these vines are easily started from seeds, often right in the garden once frost is about past. If not next to an existing fence, trellis, or other structure, make sure their supports are ready and in place early. The more vigorous the vine, the heavier weight the twine you’ll need. For the most vigorous, I use twine as farmers use in hay baling, available at farm supply stores.
If you don’t have an available fence or trellis for vines, considering placing twine from the ground to supports above, such as the eaves of roofs, or the side of a raised deck. I use tent stakes to anchor these in the ground. There are various low trellises now available made from willow branches, either fixed or that expand into teepees or tent shapes.
Vines can also be allowed to climb among branches of shrubs. One of the most creative stakes I’ve seen, and will try myself this year, was of sweet peas climbing on and through dead shrub branches stuck in the ground. This gave the effect of a sweet pea tree. When shopping, keep your eyes open for unusual structures to provide your vines. Let annual climbers be a source of color and creativity in your garden this year.
Dr. Leonard Perry is Extension Professor, Department of Plant and Soil Science at the University of Vermont. Visit his website at http://www.uvm.edu/~pass/perry/index.html