Hoya (2003)

By Janet Kister (April 2003)

Hoyas are climbing succulents that originally came from the tropical forests of India, China, Indonesia and Australia. In the Western Hemisphere, these climbers are usually of the Hylocereus, Selenicereus or Epiphyllum varieties. The hoya group is in the family of Asclepiadaceae, which is considered made up of mostly stem succulents, although to me, the leaves are the more “succulent” part of hoyas.

Common hoya names – wax plant, wax vine, wax flower and porcelain flower – originate from the plants’ leathery, waxy leaves or jewellike flowers. Wax plants are usually vines with fleshy 2- to 4-inch leaves and long-lasting clusters of one-half- to 1-inch star-shaped flowers that are sweetly fragrant and shiny.

Bob Smoley’s Gardenworld catalog lists over 40 varieties of Hoya. They allow one to select for ornamental leaf patterns, superb flowers or both.

Hoya leaves can be variegated gold and green, green with pink edges or splotches, edged with white, fuzzy, oval, pointed, veined, ivylike, large or small. The well-known Hindu rope plant, Hoya compacta, has versions with glossy, dark green, twisted leaves or curled leaves of cream, green and pink.

The flowers of Hoya carnosa are pinkish-white with red centers, but there are many other flower colors and shapes available. H. australis has red-centered, bluish-white flowers, while H. bella features white flowers with rosy violet centers. H. purpurea-fusca has purple-centered, brownish-red flowers with white hairs. H. multiflora boasts white and yellow flowers shaped like shooting stars.

Many hoya vines do very well when allowed to climb on a trellis or tiered plant stand, while other varieties are better suited for hanging baskets. The common wax plant, Hoya carnosa, has been described as a “lovely climbing plant” or “rampant grower,” depending on whether you have allowed enough space for it.

Wax plants are easy to grow in average soil mixtures. They like warmth, water and some sun, and do well outdoors in summer in sunny protected places like porches. Full afternoon sun can burn the fleshy leaves, but early-day sun encourages flowering in the summer or fall months. A few varieties prefer more shaded conditions.

These plants require plenty of warm weather and some water in winter months. Water freely during their flowering period, but allow the soil to become almost dry between waterings when the plants are resting.

Day temperatures of 70 degrees F or higher and night temperatures of 60 to 65 degrees are ideal in summer. Hoyas prefer a minimum winter temperature of 45 degrees F, but tolerate cooler temperatures if kept dry. Some leaf loss can occur under these cooler conditions.

One important point to remember regarding hoyas: Never remove the peduncles (stalks from which flowers emerge) after flowering, as more flowers will continue to be produced from these stubs.