Porcelain Flower Hoya pubicalyx

Wax plant is an epiphytic herbaceous perennial in the dogbane family (Apocynaceae). It is native to the Philippines and grows in tropical rainforests. The species epithet highlights the fact that the calyx (sepals) is pubescent.

Wax plant does best when grown in bright, indirect sunlight, such as near a sunny window. Six hours of filtered sunlight per day is optimal, however, avoid direct sunlight, as the leaves can become scorched. Direct sunlight can be provided in the morning but, limit it to no more than 2 hours. Being frost intolerant, ensure that temperatures remain above 50 degrees Fahrenheit. Cooler temperatures can lead to damaged foliage. Humidity levels should remain between 60-70%. If natural conditions do not provide the needed humidity, a humidifier can be used. Avoid placing the plant near indoor vents and heaters, as they can dry out the foliage. This plant does not mind having its roots tightly confined, so repotting is rarely necessary. Provide vertical support to allow this plant to climb. Like other succulents, providing good drainage is imperative.  Consider terracotta pots or planters that have sufficient drainage holes. Care should include watering with filtered or rainwater. During its growing season, water frequently, allowing the potting medium to dry out between waterings. During the fall and winter months, the plant needs less water and can dry out more frequently. Avoid deadheading old blooms, as the “spur” (peduncle) will produce flowers over several years. Maintenance includes trimming the plant should it become too large. 

This species has attractive silver-flecked leaves and showy flowers. The plants are slow to mature and flower; maturity may take up to two years. Its blooms are more noticeable during the nighttime hours when they are also fragrant. In too much direct sunlight, the leaves will take on a reddish color. These pigments (anthocyanins) protect its young leaves like a natural sunscreen. Mature foliage can take on an attractive silver/pink hue when sufficient sunlight is present.  

Like most hoyas, this species can spend summer months outdoors in the shade of a tree or patio. Be sure to bring it indoors when temperatures turn cool.

Insects, Diseases, and Other Plant Problems: Mealybugs, aphids, and whiteflies are some insects that are attracted to this species. Too much water can lead to root rot and leaf drop.

More information on Hoya.