Every gardener at some time or another has planted vines.
"They might have been quick growing annual vines such as morning glory, hyacinth bean, moonflower and scarlet runner bean, or perennial vines like clematis, climbing hydrangea or Boston ivy," said Greg Stack, U of I Extension horticulturist. "In any case, vines provide some vertical color and interest and perhaps some type of screening.
"Midwest gardeners also have another vine option and those are tropical vines. These vines offer some spectacular and exotic flowers as well as interest that beg garden conversation. And many of these vines are becoming easy to obtain at local garden centers. Another plus is that many of the tropical vines, while not hardy in the Midwest can be easily overwintered i ndoors and placed back out in the spring for another season of bloom. The real plus here is that because you have saved a large plant, next year's show is even more spectacular. So, what are your options in the way of 'hot vines'?"
Mandevilla or Dipladenia vine is a commonly found tropical vine in many garden centers. This vine produces a spectacle of flowers that are generously produced on a plant with shinny, waxy foliage. The flowers are trumpet-shaped with a unique twist to them and are produced nonstop through the summer. Colors range from hot pink to white, yellow and reds.
Mandevilla is an aggressive growing vine that is easily trained to a trellis or arbor and will grow four to six feet the first season. They prefer full sun and a soil that is high in organic matter and moist. Water regularly and fertilize twice a month to maintain vigorous growth.
"While these vines grow too large to overwinter as a growing plant, they can easily be stored as a dormant plant," he explained. "Leave the plant in the garden until a light frost kills back the tip. Dig up the tuberous root system and store it in a container of soil in a dark place at about 35-40 degrees over the winter. Next spring replant, and the flower display should be even better. This vine also makes an excellent container plant. Just move the whole container indoors for winter storage."
Stack said the second "hot vine" is not really a vine but more of a sprawling shrub with pliable canes that can be trained to a vertical support.
"Bougainvillea or paper flower is popular and unique because the individual small flowers are surrounded by three large petal-like papery bracts that come in almost any color you can imagine," he said. "And, because the colorful bracts remain on the plant long after the true flowers are gone, they can remain colorful for many months."
Bougainvillea prefers full sun and because they have a very fibrous, brittle root system it is best to leave the plant in the pot that you buy it in. Do not disturb the roots. Just sink the plant, pot and all, into another container or directly into the garden. Water as needed and fertilize once a month. Some pruning and tying may be needed to shape and control the plant.
When it comes time to overwinter the plant, lift the pot from the soil just before frost and cut it back to six inches. Store the pot in a cool (40-45 degrees) dark area until spring. In spring bring the plant into a warm location, remove a little bit of the soil from the top of the pot and replace it with compost and water. Do not repot. Handled this way, the plants make excellent specimens for the Midwest garden.
"Passionflower vine is perhaps the ultimate image of a tropical flowering vine," said Stack. "The blossoms are a complex arrangement of floral parts that will hold any garden visitor's attention.
"Passionflower is a vigorous growing plant and does well in a large container or planted directly in the garden. In colder areas, it can be planted along the foundation of a house. Here the protection provided by the foundation with the addition of winter mulch allows you to leave this vine in the garden where it can act as a 'hardy perennial' vine for many years. Provide a good support or trellis for the tendrils to wrap themselves around."
Passionflower does best in a full sun location and loves the heat. If you choose to grow this vine in a container, it can easily be overwintered by allowing the plant to experience a light frost to kill back the top. Cut the vine back to six to eight inches and place the pot in a cool (35-40 degrees) dark location until spring. At that time, it can be placed back outdoors, watered and growth will resume.
Clerodendrum or bleeding heart vine grows slowly enough to make it an excellent choice as a potted vine. And because these vines get better with age, it is worthwhile to consider overwintering them. The flowers of these vines are a colorful combination sepals and petals often in contrasting colors. Clerodendrum do well in full sun to light shade in a well-drained soil high in organic matter. For best blooming, fertilize twice a month and keep the soil evenly moist. To overwinter this vine, allow the soil to go dry forcing them into dormancy. Store the container in a dark place at about 45 degrees over the winter.
"Vines are versatile," Stack said. "You can train them up support structures or put them in hanging containers to cascade downward. Anyway you choose to use them, these 'hot vines' will add a tropical dimension to your garden. "