Tropical Visions (cont)
By: Victoria Matthews
* Thunbergia. Of the more than a hundred species of Thunbergia, only a few are cultivated. Probably the showiest is the sky flower (T. grandiflora), a vigorous plant from India. It reaches 20 feet (often more) and has large heart-shaped leaves. From summer to fall, it covers itself in hanging swags of mauve-blue flowers, each flower measuring about 3 inches across. T. g. 'Alba' has white flowers. Black-eyed Susan vine (T. alata) has twining stems and grows to about 6 feet. The flowers, 1 to 1-1/2 inches across, are usually bright orange with a black center, more rarely cream or yellow. It blooms throughout the summer, and if you live where winters freeze, simply treat it as an annual.
* Rex begonia vine (Cissus discolor). Some tropical vines are worth growing for their foliage, and this is such a plant. Although it's not related to the rex begonia, its leaves do look similar. The flowers are insignificant, but it is prized for its 4- to 6-inch-long deep green lance-shaped leaves conspicuously marked with silvery white (or sometimes pink) on the upper surface. The lower surface is deep red. It will climb a suitable support by means of its red tendrils. In a greenhouse, it can be trained as a spectacular ground cover, or allowed to hang from a basket, as well as being used as a conventional climber to brighten a dark corner. It is easily increased from cuttings.
Planting and Care
Start plants in pots suited to their size when you buy them, then move them to larger containers as they grow. Plant them in any good potting mix that drains well. At planting time, apply controlled-release fertilizer. If new growth yellows later in the season, supplement with any soluble fertilizer. Water before soil dries out completely, but not so often that plants get waterlogged.
Keep pots in a sunny position but watch that leaves of plants under glass don't get sunburned. During the summer, when nights are warm, pots can stay outdoors, but be sure to bring them in when nighttime temperatures are predicted to drop; bring them in for the winter well before the first frost date in your area.
Repot as needed, and prune off excess growth and errant shoots to keep growth within bounds.
Victoria Matthews, who lives in Denver, is a British botanist and garden writer with a special interest in vines of all kinds.