Hoya

( HOY - uh )

At-A-Glance Information

Commonly called Waxplant, Waxvine, or Waxflower, these tropical beauties take the form of creeping vines or shrubs. They can grow terrestrially as well as epiphytically, and typically have succulent green foliage. Clusters (commonly called 'spurs') of waxy, sweet-scented flowers appear at any time during the year. Use these plants to decorate and add sweet fragrance to outdoor spaces, grow them in containers with trellises, or use them as potted indoor plants.

Hoya Species and Varietals

The genus Hoya includes over 500 distinct species, and is a member of the plant family Apocynaceae. The genus is named for botanist Thomas Hoy. Hoya plants grow well in USDA hardiness zones 10-12. To find your zone, click here: Zone Map.

Hoya archboldiana (Papua Wax Plant)
Native to Papua New Guinea, this species is popularly cultivated as a houseplant. It was discovered in 1933, and named after the famous America aviator and explorer Richard Archbold. Large leaves are dark green and succulent, and flowers are cup-shaped and white with mauve to red-colored outlining on petals. Individual vining stems reach up to several feet long.

Hoya australis (Waxvine, Common Wax Flower, Honey Plant, Porcelain Flower)
This vine is commonly found in rainforest margins and rocky areas in Australia. This species is commonly cultivated as a vining houseplant, and produces somewhat rounded green leaves with smooth margins. The specific epithet 'australis' means 'southern'. This species is considered potentially invasive in Hawai'i, the Society and Cook Islands, and Cuba.

Hoya bhutanica (Wax Vine, Wax Plant, Waxflower)
This species, endemic to Bhutan, is considered to be an endangered species and prefers to grow in tropical, damp regions. It is commonly seen as an epiphytic plant in its natural range, and produces green waxy leaves and white flowers with pink and yellow centers that bloom in spherical flower inflorescences.

Hoya bilobata (Wax Plant, Porcelain Flower, Waxflower, Waxvine)
This trailing evergreen reaches two feet or more in length and loves to climb. This species is native to the Phillippines and was first described in 1906 by botanist Rudolph Schlechter. Leaves are green and waxy, and flowers are a pastel warm pink with yellow centers. Vining stems can reach up to 2 feet or more, giving the plant a 4-foot spread at maturity.

Hoya carnosa (Porcelainflower, Wax Plant, Hindu Rope Plant)
Native to eastern Asia, this popularly cultivated species has attractive, waxy green foliage. Flowers are sweetly scented and white with bright orange to red centers. Subspecies Hoya carnosa compacta is known as the Hindu Rope Plant, and produces folded or curled leaves and pink flowers.

Hoya cinnamomifolia (Cinnamon Hoya, Cinnamon Leaf Hoya, Cinnamon-Scented Wax Plant, Raised Vein Hoya, Porcelain Flower)
Native to the island of Java, this species is one of the largest in the genus, and produces a trailing plant with green leaves that resemble those of Cinnamomum verum (hence the specific epithet cinnamomifolia). Short-lived flowers are lime green with burgundy centers.

Hoya imbricata (Shingling Hoya, Bowl-Leaf Shingling Hoya)
This species is native to the Philippines and Indonesia. Leaves are large and green, mottled with purple and cream tones. Foliage overlaps, mimicking roof tiles, and can lay flat against buildings and other structures. Flower petals are very recurved, and are peach-yellow in color with white edges and pinkish red centers.

Hoya kerrii (Lucky-Heart, Sweetheart Plant, Lucky Heart, Sweetheart Hoya, Valentine Hoya, Wax Hearts, Heart-Leaf, Love Heart Plant)
This unique species is native to southern Asia and associated islands, and produces green heart-shaped leaves. These plants are commonly sold as single leaf cuttings around Valentine's Day (February), and produce waxy white flowers with burgundy centers. This species can produce vines that reach up to 13 feet long and was first collected by Arthur Francis George Kerr in 1910.

Hoya macgillivrayi (Red Hoya, Macgillivray's Wax Flower)
This fast-growing, vigorous vine is native to northeastern Australia and is named for William David Kerr Macgillivray, the botanist who collected the type specimen. These plants have green waxy foliage and a twining growth habit. Flowers are pink dark purple and are more closed than other species' blooms (which are usually so open that they recurve towards the base). This species is considered rare, due to seeds taking a long time to germinate and issues with poaching from its native habitat.

Hoya megalaster (Great Star Hoya, Wax Plant)
Discovered in Papua New Guinea, this species is widely cultivated as an ornamental houseplant. Leaves are large (from 3 to 8 inches long), green, and leathery to almost succulent, and flowers are pink to red. Vining stems can reach up to a few feet long.

Hoya meliflua (The Little Fraterna, Wax Plant, Waxvine, Flowing-Honey Hoya)
This species has green, stiff succulent leaves and has flowers that produce sweet nectar which drips from the center of the flower and stains petals. Flowers are commonly red to orange in color with dark centers. Variety Hoya meliflua fraterna has narrower, thinner leaves than the species. It is native to the Philippines.

Hoya multiflora (Hoya celebica) (Shooting Star Hoya, Shooting Star Wax Plant, Many-Flowered Hoya, Porcelain Flower)
This species is native to China and other tropical areas of Asia, and reaches about 20 inches tall. Leaves are long and leathery, and white flowers have long recurved portions and pink to purple central markings. This species produces an upright growing plant, but needs staking or a trellis to remain standing. Cultivars include 'Javanica' (with yellow-toned flowers), and 'WonderPhil' (also called 'Splash' or 'Silver', with variegated foliage).

Hoya obscura (Wax Plant, Red Wax Plant)
This fast-growing vine is native to the Philippines and has medium-sized green succulent leaves that will take on reddish tones when grown in sunny conditions. This Hoya plant is considered very easy to grow and is commonly sold as an indoor houseplant. In its native habitat, Hoya obscura is epiphytic to semi-epiphytic.

Hoya serpens (Wax-Flower Plant, Wax Plant, Shooting Star Wax Flower, Green Wax Plant)
This small trailing vine is native to the Himalayas and surrounding areas, and has dark green hairy leaves. Foliage sports random greyish-cream spots. Flowers are green and fuzzy with white and magenta centers. Flowers last for about a week and produce very little nectar compared to other Hoya species. This species was first published in 1883 by Joseph Dalton Hooker. Great in hanging baskets.

Hoya siamica (Wax Plant, Porcelain Flower, Hoya)
Native to Indochina, this species produces slender, green leaves and white flowers. This species was discovered by Arthur Francis George Kerr and first published in 1911. Individual vining stems can reach up to a few feet long. This species does well in hanging baskets and is also commonly trained onto trellises.

Caring for Hoya

Hoya, or Wax Plant, is a tropical plant that can be grown outdoors in warmer climates (USDA growing zones 10-12) or indoors as a houseplant. Outdoors, they should be situated in a space that does not drop below 60 degrees Fahrenheit. They do well in containers outdoors, but many species are epiphytic and are not typically planted in the ground. Choose a hanging basket or container that has adequate drainage holes on the bottom, and fill it with a light, barky potting mix (one that is good for Orchids will do). They need excellent drainage to thrive; water whenever the top few inches of soil feels dry to the touch. Situate the container in a space that receives bright, indirect light. They should not get any late afternoon direct sun, as this exposure will quickly sunburn leaves and stress the plant. Every year, check the bottom of the container to see if roots are beginning to grow through. When this happens, it is time to choose a larger container and repot the plant. Prune in springtime, removing about 1/3 of the length of each vine. Pruning will keep the plant looking fresh and bushy and clean up straggly growth. Fertilize yearly in early springtime with an application of compost around the base of plants. Hoyas typically live for a few decades (some species can live up to a century in their native habitats) before needing to be replaced in the garden.

Growing Hoya Indoors
As indoor specimens, these plants prefer to be situated in a warm, humid location with bright indirect light. Hoyas will do best with temperatures between 65 and 80 degrees Fahrenheit, and like to be in an environment with a humidity of 40-60%. Mist plants regularly to provide adequate humidity for best growth. The more light these plants receive, the more they will bloom. If they are not receiving enough light, for example if they are grown in medium indirect light, they will tend to drop foliage and not flower. Increase available light using grow lamps if needed. Keep the soil moist but not wet, watering somewhere between once every one or two weeks. More frequent waterings are needed in warmer, drier months and during the active flowering period. During wintertime, these plants go somewhat dormant, and will need fewer waterings. Never leave roots sitting in water; this will cause the plant to develop root rot. Prune plants with sanitized scissors or clippers, removing up to 1/3 the length of each vine in early springtime. Check the bottom of pot regularly to determine if roots are attempting to grow out through the bottom drainage holes. Once roots emerge, it is time to pot up. If your plant has become root-bound or if there are sections of roots that have died since it was last repotted, this is a good time to break up those roots or trim some off.

Propagation

Hoya plants are most easily propagated through taking cuttings of an existing plant and rooting them. To propagate your Wax Plant, follow the instructions below:

Propagating Hoya by Cutting

Take a 3-node soft stem cutting from the end of a non-blooming stem, cutting at a 45 degree angle with sanitized shears or scissors.
Remove all but the top two to three leaves from the cutting and then dip the cut end into rooting hormone and tap to remove excess powder. Alternatively, you can simply leave the cutting out for a few days and allow the cut end to callus over.
Place the cutting in your prepared propagation container, and water, ensuring that good drainage is occurring. Continue to provide water regularly to these new cuttings, and in about 2 weeks roots should be forming at the base of the cutting.
Resume regular care instructions (see above).

Problems and Pests

Certain species are considered invasive in some regions; see the species descriptions above for more information. Check with local authorities before planting. Hoya plants are susceptible to the following issues and pests: