For those who love indoor greenery but hate the hassle of caring for houseplants, hoya may be the perfect solution. These tropical, drought-tolerant plants are easy to grow, nearly carefree, and as an added bonus, most varieties produce fragrant, star-shaped blooms. Although they grow outdoors in the tropics, hoya plants are usually grown as houseplants in the United States. Hundreds of hoya varieties exist, and many types are available at nurseries and garden centres or via mail order.
Hoya is a succulent or semi-succulent plant that often grows naturally as a climbing vine. The leaves may be dark green, light green or variegated, straight or twisted, as small as a fingernail or nearly as long as a forearm. Hoya kerri has leaves that look like valentine hearts and white flowers with burgundy coronas, while Hoya polyneura is often called "fishtail" due to the shape of its foliage. In addition to vining varieties, hoyas are available as small, bush-like plants, trailing plants, dwarf plants or miniatures.
The most readily available hoya in garden centres and nurseries is probably Hoya carnosa, also called wax plant. This hoya is a climber that produces fragrant white flowers. Hoya carnosa variegated cultivars include exotica, which has yellow and pink, variegated leaves; variegata, with curled green leaves edged in creamy white; and krinkle 8 variegata. Rubra, also called Krimson Princess, produces small globes, or umbrels, of tiny pink flowers. Agentea picta, also called Hindu rope, has tightly twisted foliage and a trailing habit.
Miniature wax plant, Hoya bella, is a native of India. This upright, shrublike plant produces flat clusters of white flowers in the classic hoya star shape. Once flower buds appear, do not move the plant. Hoya bella is poisonous. The plant is a bit of a climber but does not twine. Hoya bella makes an attractive, trailing-form hanging basket plant.
Dark red in the centre with yellow petals, the flowers of Hoya multiflora are often called "Shooting Stars" because the petals are swept back as if flying through space. Multiflora is a shrubby plant that only grows 12 to 18 inches tall. The plant flowers year around.
Hoyas root readily from stem cuttings, or you can purchase young plants from commercial nurseries or garden departments. The plants thrive outdoors only in U.S. Department of Agriculture hardiness zones 10 to 12. To grow as a houseplant in any zone, plant the hoyas in a pot filled with a loamy potting mixture. If the pot has no drainage holes, place pebbles or broken clay pot pieces in the bottom of the pot before adding soil. Plant the hoya no deeper than it was in the original container. Most hoyas are drought-tolerant. Water the plants when the soil is dry. Place the pot where it will receive several hours of bright light daily. In winter, the plants get along fine with less light and water, but try to keep them warm. Hoyas prefer temperatures no colder than 10 degrees C.
- Missouri Botanical Garden: Hoya Carnosa
- University of Florida IFAS Extension; Hoya Carnosa Wax Plant, Wax Flower; Edward F. Gilman; 1999
- University of Florida IFAS Extension; Wax Plant (Hoya) Production Guide; R.W. Osborne, et al.
- Succulent Plants; The Hoya Plants Page; Christina M. Burton; 2007
- PlantCare: Miniature Wax Plant
- Texas A&M University: Plants Suitable for Hanging Baskets