The wax plant (Hoya carnosa) has fragrant clusters of star-shaped white blossoms that appear from late spring to fall. Because they're pollinated by night-flying insects, the flowers have no scent in the day, but a heavy sweet scent at night.
The stems have fleshy 3-inch leaves and sap the color of maple syrup or honey. The wax plant is easy to propagate and grow, so it's often passed from one generation to another like an heirloom plant. The climbing species need support from canes or trellises, and trailing species are attractive in containers.
Common name: Wax plant, honey plant, porcelain flower
Botanical name: Hoya carnosa
Plant type: Climbing or trailing succulent
Height: 20 feet in its native habitat of India and South China
Zones: 12 and higher for outdoors; 50°F to 60°F minimum indoors, depending on cultivar
- Light: Indirect or bright filtered light indoors; full sun with some shade outdoors
- Soil: Indoors use a potting mix with humus, sharp sand, ground bark, and charcoal; outdoors plant in moist, well-drained soil.
- Moisture: Water well during flowering but let soil become nearly dry between waterings in winter.
- Pruning: Trim back after the hoya flowers, if needed, to control size.
- Fertilizer: Apply a balanced fertilizer monthly.
Pests and diseases
- Mealy bugs and scale occur.
- Root semi-ripe cuttings in late summer.
- Layer in spring or summer.
- ‘Crispa' (Hindu rope plant) has weeping stems and convoluted leaves that make it look like a rope. It has small, waxy white flowers in summer and mounds 6 inches tall in containers, with stems that trail down rather than climbing. Minimum temperature is 60°F.
- ‘Crispa Variegata' (variegated Hindu rope plant), pictured here, has curled and twisted leaves with white and pink variegation. Its fragrant pink flowers bloom spring to fall. The foliage mounds 3 to 5 inches tall in containers and then trails down. Minimum temperature is 50°F.
- ‘Krinkle Kurl' has contorted leaves that fold up lengthwise. It has white flowers and a climbing habit. Zones 12 and higher when planted outdoors.
All in the family
- Hoya archboldiana is a vining hoya with deep yellow to maroon flowers. The plant mounds 2 to 3 inches tall in a container and then vines. Grow it in partial sun with a minimum temperature of 60°F.
- Hoya australis is another attractive vining hoya. It bears fragrant, white blooms summer through fall. Place it in partial sun. It mounds 10 inches tall in a container and then vines. Minimum temperature is 60°F.
- Swamp milkweed (Asclepias incarnata) and butterfly weed (Asclepias tuberosa) are other members of the Asclepiadaceae family. They both have milky sap in their stems, typical of this family.
- Another member, Madagascar jasmine (Stephanotis floribunda), is a sweetly scented vine with tubular flowers. It's cultivated for its long-lasting waxy white flowers and intense fragrance. The scent is strongly reminiscent of the true jasmine, Jasminum officinale.
Text by Mary Pestel, photo courtesy Logee's Greenhouses, www.logees.com.