Hoya carnosa, often referred to as wax plant or porcelain flower, is a tropical plant with a semi-woody vine. It is from the Asclepiadaceae family, the same family as milkweed. It is considered a low-maintenance houseplant with several different cultivars.
Hoya Carnosa Appearance
This Hoya plant produces long, thin vines growing up to 20 feet (6 m) long. The leaves grow 3 to 6 inches (7.6 to 15.2 cm) long and 1 to 3 inches (2.5 to 7.6 cm) wide. These deep-green leaves are sometimes speckled with creamy-white or silver markings. The waxy coating on the leaves, called the cuticle, help retain water.
The blooms of the Hoya carnosa are star shaped and grow in clusters of up to 30 flowers. The individual blooms sport four to five petals in either white or pink. These shiny blooms appear in spring to fall, depending on the cultivar. They give off sticky sap, so be careful hanging these Hoya plants near furniture.
Hoya Carnosa Lighting Requirements
This Hoya plant prefers bright, indirect light near a sunny window. Non-variegated varieties can tolerate the higher lighting conditions of a south-facing window, but variegated plants will do better with northern window exposure. Too much direct sunlight will cause the leaves to dry out and turn yellow.
Keep your Hoya plants away from hot or cold air vents and do not let them touch cold windows. This will stunt the plant’s growth, damage leaves, and cause buds to drop. Proper lighting will encourage your Hoya plant to produce more blooms.
Watering and Soil
Allow the top two to three inches of soil to dry out between watering. When watering, soak the soil thoroughly but don’t allow excess water to remain in the pot’s drip tray. Extended exposure to water can cause root rot.
Overwatering or underwatering your Hoya carnosa can cause blooms to drop. If this occurs, adjust the watering schedule accordingly. Moving plants actively blooming changes their sunlight exposure and can also contribute to lost buds.
Ensure the soil mixture for your Hoya plant is well-draining. Use a mix containing organic material, such as peat moss, to hold water. Adding pine bark or perlite to the mix will encourage proper drainage and help prevent root rot.
Temperature and Humidity
Hoya plants prefer high temperatures and humidity levels. During the growing season, temperatures of 65 Fahrenheit (18 Celsius) at night, and 80 Fahrenheit (27 Celsius) during the day are optimal. Temperatures of 50 Fahrenheit (10 Celsius) or lower will force the plant into dormancy.
Keep the humidity levels surrounding your Hoya carnosa at least 30 to 40 percent. Humidity of 60 percent is ideal and will encourage faster growth and more blooms. To increase humidity near your plant, place the pot in a saucer filled with gravel and water.
Pruning and Propagation
Prune these Hoya plants in spring before vigorous growth starts. Snip the vine below a node, a little shorter than the desired length. Don’t remove any more than a third of the foliage at one time to allow the plant to rebound. Leafless stems, called spurs, should not be pruned. These spurs produce the blooms for your Hoya plant each year.
This Hoya plant propagates by cuttings from a mature plant. Snip a healthy vine with two to three leaves to a length of 4 to 5 inches (10 to 13 cm).
Place the cutting in either a glass filled with rainwater, or a pot filled with half African Violet soil mix and half perlite.
The cuttings will grow roots within three to four weeks. If placed in water, transfer the rooted cuttings to a pot with a balanced soil mixture. The cutting will grow to a mature plant in approximately two years.
Hoya Carnosa Pests and Disease
This disease presents as a large, grayish area on the plant’s leaves. It causes the leaves to collapse and become mushy, typically in the center. Botrytis blight usually appears in the cooler, winter months due to excess watering. To correct this disease, provide your Hoya plant with less water and increase the ventilation around it.
Potting mix containing peat can attract the fungus gnat, a fly-like insect that crawls on the soil’s surface. Mealy bugs are also common and appear as small, white, fuzzy insects. Use horticultural oil, as directed, to rid your plants of these pests.
Spider mites are less common Hoya plant pests but do more damage. Look for fine webbing between the plant’s stems and, if present, cut off those affected. To rid your plants of them, place it in a sink or shower and treat with an insecticide specifically for spider mites.
The Hoya carnosa plant will bring you years of enjoyment provided you follow their simple care instructions. They produce beautiful blooms and make an excellent addition to your home and Hoya plant collection.
In a rush? Here are 10 Hoya varieties for beginners to discover:
Hoya Carnosa FAQ
Yes, in a frost-free zone with mid-level sunlight exposure.
Hoya carnosa has a fast growth rate.