While sorting through the heady phrases used to describe jasmine's scent, one becomes convinced that this flowering houseplant has no equal: "intensely aromatic," "the scent of French perfume," "delicious essence," and "the poet's flower." These descriptions alone explain why this flowering vine is cultivated as an indoor plant.
Most species of jasmine grown today were originally native to tropical Asia and parts of China. The jasmines that can be grown as houseplants are tropical or subtropical vines or subshrubs grown for their fragrance. While there are over 200 species grown throughout the world, only a few can be successfully grown indoors.
The cultural requirements of the indoor varieties of jasmine are the same (with the exception of the cool-weather jasmine). They all need bright light with at least four hours of direct sun per day. In spring and summer, water regularly and fertilize every two weeks with a high phosphorus fertilizer to encourage good flower development. If possible, place the vine outside in direct sun for the summer (after a gradual period of acclimatization to the outdoors). Pruning and repotting should take place in spring. Jasmine, like many other tropical flowering plants, requires at least a 15-degree difference between day and night temperatures.
Jasminum polyanthum, the winter-blooming jasmine (sometimes called Chinese jasmine) is one of the easiest to cultivate and is a favorite among growers. A vigorous climber, it usually blooms around Valentine's Day with pink buds opening to masses of white fragrant flowers. J. polyanthum requires much cooler growing conditions than many of the other varieties and can actually tolerate temperatures between 40 and 50 degrees from September until the plant sets its buds. During this cool autumn and winter period, water the plant only when the soil has dried out. As with all jasmines, a summer spent outdoors in full sun is the preferred warm-weather treatment.
Another cool-weather jasmine is the Jasminum officinale grandiflorum. This is the famous "French perfume jasmine" grown throughout the fields of southern Europe, where it blooms profusely from June to October. The potency of the fragrance is so strong that the flowers continue to produce fragrant oils even after being picked. As an indoor plant, it only does well if given a cool (40 to 50 degree) greenhouse where it can climb. Feed this vine heavily in spring as it begins to set buds for summer and fall blooming.
Jasminum nitidum, the angel-wing or star jasmine, is one of the warm-temperature jasmines that does quite well in 65 to 80 degrees. It is a very bushy vine, considered ever-blooming in its native New Guinea, but slightly less profuse when blooming indoors. The glossy green foliage sets off the pure white, star-shaped flowers of "heavenly" scent. Some growers have been able to increase its bloom time by providing it with a half-day of direct sun rather than just four hours and by judicious pruning and pinching.
Another popular warm-temperature jasmine is J. sambac (Arabian jasmine), and especially its two well-know cultivars, 'Maid of Orleans' and 'Grand Duke of Tuscany'. This species is one of the oldest cultivated, and its buds are prized by the Chinese for the fragrance they lend to tea as well as for their use in religious ceremonies. 'Maid of Orleans' has semidouble, smaller, but intensely fragrant flowers, a long bloom time and a nice compact shrublike growth that makes it a good candidate for windowsill culture. 'Grand Duke of Tuscany' is also a bush type with true double blossoms of very large and even more fragrant carnation-size flowers. Both cultivars can either be pruned right after blooming or their stiff, upwardly climbing branches can be woven through a low window trellis or even miniblinds.
Whether trained around a wreath form, trailing down from a hanging pot, or vining up an indoor trellis in a sun-filled window, the glossy leaves and exotic perfume of jasmine set the scene for a tropical winter landscape. Come see and smell fragrant jasmine in the Garden's Greenhouses this winter.