The wax plant Hoya carnosa [HOY-ah karn-OH-suh] has been a favorite houseplant for decades.
Many of us remember seeing the “Hoya” in their grandmother’s kitchen. Over time cuttings passed through families and shared among friends.
Hoya also picked some other common names:
- Wax vine
- Wax flower
- Porcelain flower
- Honey plant
- One variety is called the “Hindu rope plant”
Hoyas were named by botanist Robert Brown in honor of botanist Thomas Hoy.
This plant is:
- Easy to care for
- Produces beautiful flowers
- Excellent at cleaning the air indoors
No wonder it has enjoyed such enduring popularity.
What Is The Plant’s Origin?
The wax vine Hoya originates in East Asia and Australia.
But this easy-to-care-for house plant has been in cultivation for more than 200 years and popular around the world.
What Is The Wax Flower Related To?
Hoyas are part of the Asclepiadaceae family.
There are many species of Hoya, which can grow as a creeper or vine, and rarely as a shrub.
Only a few of the Hoya species are commonly cultivated as houseplants.
Growing The Wax Plant
Size: Porcelain flower plants are long-lived and will grow in tendrils 2-4 feet long, depending on the cultivar. These tendrils can be allowed to cascade from a hanging pot, or trained as a vine.
Flowering & Fragrance: Hoyas are famous for their umbels of delicate, highly fragranced, star-shaped flowers, in creamy shades of white and pink. These flowers will sometimes drip nectar onto surfaces below the plant.
Light & Temperature: Hoyas require bright, but indirect lighting. While the plant will tolerate lower light conditions, it will not bloom without sufficient light. As tropical plants, they prefer temperatures between 60-85 degrees, and will not tolerate prolonged chill, or survive a frost.
Watering & Feeding: These plants prefer to dry between watering and require well-drained soil. The thick, waxy leaves retain water like succulents, so you can wait until you see the leaves contract and pucker a bit before watering. They can be fed with an epiphytic fertilizer during the growing season, but it is not necessary.
Soil & Transplanting: Wax flowers require excellent drainage, so a soil mix with large particles like perlite or pumice is necessary. Consider blending a light, airy African violet soil mix with the large particles of an orchid mix to provide good nutrition and aeration at the roots. Wax vines bloom best when slightly root bound, so do not size up pots too often.
Maintenance: The biggest mistake newcomers make when living with Hoya flower is to trim their spurs. When mature, the plant begins to produce stem-like structures called spurs.
While it may take time, flowers will eventually form and bloom from those spurs, and, when the flowers are bloomed out, the spurs will grow and produce new flowers year after year. Trimming a spur or cutting it after the blooms have died will inhibit future blooming.
How To Propagate Hoya Carnosa Plants
Wax vines propagate easily from cuttings or by layering. Growing from seed is slow, and seeds are unreliable germinators, so cuttings are preferred.
Propagate Plants By Layering:
- Choose a strong, healthy, low-growing stem near the surface of the soil
- Use “pins” to tuck the plant stem at the joint below the level of the soil
- Pin part of the stem attached to the parent plant, and the other part growing normally
- Keep the soil moist below the submerged stem, and roots will form in a few weeks.
- Snip the new rooted stem free from parent plant and grow independently
Growing Wax Vines From Cuttings:
- Take a healthy cutting from the parent plant in spring or summer, when it is the growing season
- Choose a stem 5”-8” inches long, with at least two growing leaves
- Cut the stem with a clean, sharp blade
- Place the stem in a glass of water or soil (if using soil dip cutting in a rooting hormone)
- Keep it in a location where it gets lots of bright light
- Wait until the roots are 3”-6” inches long before placing the cutting into a pot
- Propagating cuttings is also a great way to keep a thriving indoor garden.
- Seasonally prune the plant, or a stem if it accidentally breaks off.
Caring For The Wax Plant
Wax flowers are famously easy to care for, but they do have their preferences. Keep them in a north-facing window for indirect lighting all day, or an east-facing window for bright morning sun, without afternoon heat.
As mentioned above, the leaves will indicate when the plant is ready for water. It should be watered more in the spring and summer growing season, and less in winter months.
You can provide a liquid plant food every 3-4 weeks in the spring to encourage more vigorous growth.
Pests, Disease Or Problems The “Honey Plant” Encounters
Most diseases of the wax hoyas are associated with overwatering or poor soil drainage. These conditions can be exacerbated by the fact that these plants seldom require transplanting.
Potting soil can break down and lose drainage over time, or minerals can build up in the soil from the water.
If you see the leaves yellowing or looking weak, withhold water and consider transplanting to new soil if it’s been a couple of years.
Spider mites, aphids, and mealy worm infestations sometimes attack the wax hoya, although it is rare. I that case, gently clean the leaves on both sides with warm water and a gentle cloth and follow up with neem oil treatment.
Porcelain Flower Tips, Tricks, And Suggestions
While the fantastic foliage and attractive cascading habit of wax vines are reason enough to keep it, many people particularly want their plant to bloom so that they can enjoy the heady fragrance of the flowers. Here are some tips to promote blooming:
The wax flower only bloom when mature, and it may take years for these long-lived plants to reach maturity
Plants will not bloom when they do not receive enough light. Consider relocating the plant to a brighter spot, without direct afternoon sunlight
They bloom best when slightly root-bound, so do not transplant into larger pots too often. However, do not stress the plant by transplanting it into a smaller container hoping to promote blooming. Be patient
A plant may produce spurs in the spring that do not develop flowers that year. Leave the spur undisturbed, and provide an all-purpose plant food every few weeks the following sprint to encourage blooming. Healthy spurs will continue to grow and produce flowers year after year
Never repot or move the plant while it is in bloom, as this may cause blooms to drop.
Best Ways To Use In Design – Indoors Or Outdoors
Plants may get too long and stemmy, in which case you may want to prune it in the spring. This will help encourage fuller growth and add dimension to the plant. Do not prune the flowering spurs.
Use hoya vines to accentuate your décor, it’s important to celebrate and feature the foliage, since blooms may be reluctant to appear. Mix several species in the same container, for the most visual interest in variegation and leaf coloration.
Use a wax vines in a hanging container and let it trail over the sides, for a beautiful showpiece. Or wrap it gently around a vertical support, training it up a trellis.
Remember that, should it bloom, the prolific flowers may drip nectar onto the surface below, so be mindful of messes or insects that are attracted to the sweet droplets.
When buying a hoyas, look for one with healthy foliage, and inspect it carefully for any signs of insects.
What Are The Most Popular Species And Varieties?
Hoya carnosa is the most popular species because they produce the largest and most reliable flowers.
Popular cultivars include “variegated,” with creamy white edged leaves; “crinkle,” with textured, wrinkled leaves; and “krimson queen,” whose flowers are brighter pink with hot pink centers.
Hoya Bella is a species with smaller, more delicate leaves, and Hoya australis has tiny, honeysuckle-scented flowers.
The wax plants is a lovely complement to nearly any home. It is attractive, cleans indoor air, produces wonderfully scented flowers, and is easy to care for. It can be part of your own family for generations.