Mandevillas

Flower & Garden Magazine, Dec, 1996 by Tovah Martin

When I Found a Mandevilla sitting proudly in the post office window, I knew the plant had finally achieved superstar status. There is sat, soaking up the sunbeams beside mug shots of various federal offenders, blooming its foolish heart out despite considerable negligence in care and feeding from the postal employees. Actually, I shouldn't have been surprised to bump into that bright-red bloomer blithely loitering in the lobby. Mandevillas might not be as omnipresent as geraniums, but they're certainly gaining prestige.

The mandevilla most often encountered in post offices and elsewhere is Mandevilla sanderi 'Red Riding Hood.' Generally mislabeled as Dipladenia sanderi (although the name was ditched by botanists some 25 years ago). M. sanderi 'Red Riding Hood' has won fame for its stubborn refusal to stop blooming. At any time of year, you'll find its shiny-leafed branches brandishing 3-inch-wide, lipstick-red blossoms, each accented by an equally vivid yellow throat. The color is slightly startling, but no more so than your average cherry-colored geranium -- and it's even easier to please than that cheerfully colored standby.

'Red Riding Hood' is a fairly new invention. But its parent, M. sanderi, has been around quite awhile. Introduced from Brazil in 1841. M. sanderi is a wispy, roving vine occasionally crowned by subtle pink blossoms. The petal hue is subdued compared to its garish offspring, but buds appear only on mature specimens -- and maturity can take a dozen years or more. The plant definitely needed some improvement if it was to attain stardom.

The awaited improvement was achieved in 'Red Riding Hood.' It appeared on the market about 15 years ago boasting prolific, eyeriveting flowers borne on plants with a compact growth habit that tends to droop downward rather than requiring a trellis. On the heels of 'Red Riding Hood,' a flurry of further hybridizing created more cultivars, including 'Scarlet Pimpernel,' with flowers that display a slightly more electric shade of scarlet, and 'My Fair Lady,' bearing blossoms that are bleached such a pale pink they seem nearly white from afar. The new hybrids tend to pause in their flower production for a month or two in the depths of winter. But besides that minor shortcoming, they possess all of the other fine attributes of 'Red Riding Hood.'

'Red Riding Hood' is certainly the celebrity in the family, but Mandevilla x amabilis 'Alice du Pont' can be rated as a close runner-up. Originally developed for greenhouse purposes at Longwood Gardens in Pennsylvania, this large-leafed, majestically flowered vine didn't become familiar to the general public until it changed careers. Nowadays, 'Alice du Pont' finds employment as an annual out doors. A gallon-size pot of this vigorous vine slipped into the ground in spring will easily cover a fence in a single season, camouflaging its support in a profusion of broad, deeply textured foliage and equally abundant 4inch-wide luminous pink trumpets. 'Alice du Pont' continues to blossom throughout the summer, but the plant's large dimensions make it a bit too cumbersome for the post office or similar applications. Even when it's contained in a pot, 'Alice du Pont' will rapidly engulf a 3- to 4-foot trellis. And it rarely produces those divinely beautiful, pearly pink blossoms in the winter. 'Alice du Pont' is most suitable as a fast-moving annual landscape vine, a patio plant or a tropical greenhouse bloomer.

'Alice du Pont' and 'Red Riding Hood' are the high-profile members of the genus, but some lesser-known mandevillas are definitely worth considering. Although not yet readily available, Mandevilla boliviensis boasts an abundant crop of white trumpeted blossoms accented by yellow throats amidst an energetic, shiny-leafed vine. And M laxa is a fragrant white bloomer that grows by leaps and bounds in summer but slips into dormancy during the wintertime. They all hold promise. Although most mandevillas are not quite as willing to endure the in clement growing conditions that 'Red Riding Hood' tolerates in our local post office, they will grow and flourish indoors on a warm, sunny windowsill.

Ideally, mandevillas should be given a generously large container with a fertile, well-drained soil underfoot. They prefer nighttime temperatures that remain above 65 degrees with a 10- to 15-degree rise during the day. If grown in cooler conditions, they tend to drop leaves during the winter but will sprout anew come spring. Mandevillas are hungry plants and should be fed once every three to four weeks with 20-20-20 or any balanced fertilizer. If all goes well, the vining types will require a sizable support on which to clamber.

Mandevillas are not winter hardy outdoors. In autumn, cut the vine back ruthlessly and carry it indoors before the first frost. A large, warm, sunny, south-facing window would be the ideal home for the plant during the winter. Or offer your mandevilla as a gift when you pick up your mail.

Frequent contributor Tovah Martin most recently wrote about Convolvulus sabatius in our August-September 1990 issue.