Hoya Carnosa: Wax Plant Care

The Hoya carnosa plant is renowned for its waxy flowers and foliage.

This evergreen, semi-woody, twining plant has delightfully scented blooms are in numerous clusters, with five symmetrical outer lobes on each floret.

Typically, they are white, cream, or pink in color, with black, star-shaped centers.

There are variations, such as Hoya carnosa Krimson Queen, and Hoya carnosa Compacta (also known as Hindu rope plant), which is one of the most famous hoya plants because of its curled, meaty leaves and lengthy vines.

In this post, we will cover what a Hoya carnosa plant is and how to care for it.

What is a Hoya Carnosa Plant?

The Hoya carnosa plant is an evergreen, semi-woody twining vine that is known for its waxy flowers and foliage. 

Its sweetly scented flowers bloom in multiple pretty clusters, with each floret consisting of five symmetrical outer lobes.

These are usually white and cream, or shades of pink, with darker, distinctly star-shaped centers.

What Is A Hoya Carnosa Plant

Its leaves are 2 to 3 inches long and nearly oval in shape, and they are arranged opposite one another along the long stems. 

The plant has a shallow root system, and in the wild it grows epiphytically, finding trees and rocks to support its growth.

When Hoya carnosa grows too large to climb, it often hangs downwards or trails along the ground. 

Hoya carnosa is commonly called the wax plant, and sometimes wax vine or porcelain flower because its blooms look just like fine china. 

There are hundreds of different hoya species, but Hoya carnosa is undoubtedly the most commonly grown type. 

Most Popular Hoya Carnosa Plant Variants

There are several different species as well as cultivars and hybrids.

Amongst these, you will find the colorful Hoya carnosa variegata, which includes the Hoya carnosa Krimson Queen (Tricolor) and Hoya carnosa Purple Pride cultivated varieties.

Additionally, there is the most well-known variant called Hoya carnosa compacta—commonly known as the Hindu rope plant.

Hoya carnosa Krimson Queen (Tricolor)

Hoya carnosa cv. Krimson Queen, also known as Hoya carnosa cv. Tricolor, has stunning leaves in shades of pink, white, and green, all with unique variegations.

You can identify it by the white or cream border on its leaves. Sometimes the stems are bright pink in color, and they shoot out solid creamy-white leaves.

Hoya carnosa compacta

The Hoya carnosa Compacta is one of the most popular hoya plants to own due to its curled, meaty leaves that grow on long vines. 

It has leaves that are waxy with flowers that look like porcelain. It has twisted, waxy leaves that arise on long vines like ropes, making it an ideal plant to grow in hanging baskets.

Because of the waxy leaves, this plant has been called the wax plant amongst other names, such as porcelain flower, Hindu rope plant, rope hoya, and even Krinkle Kurl!

This variety of Hoya carnosa will eventually produce magnificent clusters of star-shaped pink blooms as it matures.

Origins of the Hoya Carnosa Plant

The Hoya carnosa plant can be bought anywhere in the world, but it is native to eastern Asia, Australia, and the Pacific Islands. 

A Scottish botanist and plant collector, Robert Brown, originally discovered Hoya carnosa when he visited Australia in the early 1800s.

He named the plant after a close friend, Thomas Hoy, who was also a botanist. 

Where to Grow Hoya Carnosa Plants

Where To Grow Hoya Carnosa Plants

Although it is grown outdoors in tropical environments, Hoya carnosa has become an immensely popular houseplant.

You can grow it outdoors, in the ground, in USDA Hardiness Zones 9–11 without any problems.

But it won’t survive outdoors in frost and snow, and it doesn’t like too much sunlight. 

Hoya carnosa plants adapt well to an indoor environment as long as you mimic the outdoor conditions they thrive in. For instance, they like natural filtered light and high humidity.

If your Hoya carnosa plants don’t get sufficient light and humidity, or if the watering isn’t ideal, they probably won’t flower.

At the same time, they will withstand more severe temperatures, and they don’t need much attention. 

If you’re planning to keep a Hoya carnosa plant outdoors some of the time, you will need to make sure that the temperature at night doesn’t fall below about 60-65 degrees Fahrenheit. 

How Big Will My Hoya Carnosa Plants Get?

While Hoya carnosa will grow upwards, horizontally sideways, or downwards for more than 3 feet in its natural environment, it’ll take a long time to get there. 

People who value them as houseplants generally accept that they are slow-growing.

In the garden, you can let them do their own thing, and they will stretch and spread as high and wide as you let them. But again, it’s going to take time. 

How to Care for Hoya Carnosa Plants

Hoya plants are exceedingly long-lived plants that have deep green, vining foliage and produce fragrant, star-shaped, light pink-ish red blooms.

Due to their thick waxy foliage, they are commonly referred to as wax plants or porcelain flowers, referring to the peculiar texture of their blossoms.

These tropical vining plants require a few simple conditions, such as providing them with bright, indirect light, humidity, and some light watering.

Lastly, use a well-draining potting mixture to promote air circulation and you’ll enjoy your Hoya carnosa plant for a long time.

Temperature and Climate

Temperature And Climate For Hoya Carnosa Plants

Hoya carnosa can survive temperatures as high as 70 to 80 degrees Fahrenheit. 

All are pretty hardy plants that can be cultivated indoors or outdoors in frost-free climates.

They are definitely not cold-hardy; they cannot withstand freezing conditions for an extended period of time, which is quite obvious given that they originate from tropical locations.

Temperatures below 50 degrees Fahrenheit should be avoided.

Hoya plants thrive under high humidity but are more tolerant indoors when humidity levels are moderate. A humidity level of 40-60% is a good target to shoot for.

Although hoyas can tolerate a wide range of humidity levels in the home, they grow faster when humidity levels exceed 60%.

You should place your Hoya carnosa plant in a pebble tray, which is basically putting your pot on top of a layer of rocks (or pebbles) and a small amount of water that evaporates upwards, increasing humidity around the plant.

Misting is an acceptable method for increasing high humidity.

Just make sure you don’t mist your Hoya when it is blossoming or flowering, as it may cause bacteria and fungus to grow.

Light

Hoya carnosa plants thrive in bright light, although direct sunlight is acceptable, especially when the plant is beginning to bloom.

It’s best to give it approximately two hours of direct sunshine in the morning or evening, but too much direct sun exposure may burn or yellow their leaves.

If you have the plants indoors, place them in windows facing south or west because they will get the best indirect light throughout the day.

During the winter months, when there is less sun, a wax plant can benefit from artificial light.

Simple fluorescent lamps will work just fine, but if you want to get a little better light for your plant, you can invest in a simple grow light setup.

Basically, grow lights are highly recommended for maintaining plant growth and ensuring proper flower blooms.

Watering

Watering Hoya Carnosa Plants

A decent rule of thumb is to water the Hoya carnosa plant regularly or when the leaves begin to slightly pucker. This is most likely when the soil has dried out.

However, letting the soil remain excessively dry for too long can harm the Hoya plants.

During the spring to fall seasons, water your Hoya carnosa by keeping the soil slightly damp but not overly wet. Allow the top inch of soil to dry out between waterings.

We think you should water these plants lightly once a week and mist them twice a week.

However, during the fall and winter, water your plants sparingly so that the soil does not dry up.

As with other plants, a hoya plant does not do well when you overwater it. Excessive water can cause the plant to wilt and die.

Hoyas are tropical plants that flourish in moist environments. You can utilize a humidifier to increase the humidity, particularly in the winter when the indoor air tends to be dry.

Soil

Hoya carnosa plants thrive when planted in potting soil that offers excellent air circulation.

To get the ideal soil mix, you can combine a cactus mix, an orchid mix, and perlite in equal parts.

If you can’t find any orchid mix, some of our gardening friends mix coconut coir, potting mix, and perlite in equal parts.

Hoya carnosa plants will flourish in soil that is permeable but still capable of retaining rainwater.

So, to be honest, what matters is that you mix some airy soil amendment such as perlite so that the mix can drain water out but at the same time retain some moisture.

Fertilizer

Fertilizer Hoya Carnosa Plants

Hoya carnosa plants, like any other houseplant, prefer some fertilizer.

You should only add fertilizer in the growing season, which is in the spring and summer.

Add fertilizer to your hoya carnosa once every month with a liquid fertilizer or slow-release type fertilizer.

Once cold weather arrives during the winter, reduce (or even cease) adding fertilizer. During this time, hoya plants will go into dormancy and do not need very little fertilizer, if at all.

Propagation

You can propagate Hoya carnosa plants using:

  1. Stem cuttings in the soil
  2. Stem cutting in water
  3. Propagating by layering.

We recommend using stem cuttings as we think it is the easiest method.

Firstly, they only propagate during the growing season, which is spring or summer; they will produce roots and grow more quickly than in the winter when they are dormant.

Begin by cutting the stem from a healthy plant. Each stem cutting should be around 3 to 6 inches long and have at least 2 to 6 leaves.

Now, you have 2 choices for methods to promote root development in your stem cuttings. You can place it in the soil or water.

We like to use water because you can monitor it over time. Using a glass of water, place the stem cuttings in the water and wait till they produce roots that are 2 to 3 inches in length.

Plant it into a new pot once the roots have sprouted, making sure there is enough stem below the soil’s surface to support the plant.

Repotting

Hoya plants prefer to be confined or crowded in their containers. They only require repotting every two or three years.

However, if you observe any of the following, it may be time to repot your hoya plant into a larger container.

  1. A dense carpet of roots covers the surface of the container. If you observe this, your plant’s roots are likely crowded.
  2. You’re watering significantly more frequently than you used to since the soil or potting mix is drying up significantly faster than usual.
  3. There are numerous roots emerging from the drainage holes.
  4. Your plant appears to be exceptionally big for its container, and its development has slowed significantly or may have completely stopped.

There are 3 easy steps to repotting your wax plant.

  • First, remove the hoya plant from the pot and loosen any soil from the root ball.
  • Next, choose a pot that is several inches larger than the old pot.
  • Lastly, plant your wax plant in some fresh soil.

Pruning

Wax plant pruning is to be done in spring and summer, which is the growing season.

By removing and pruning the long stems, the plant will appear fuller. In addition, stem cuttings can be used for propagation purposes.

When pruning the stems, start from the bottom leaves. Snip the vine just below a node at a length somewhat shorter than the desired length.

Do not take off more than one-third of the plant’s foliage at any given time. The plant branches will eventually produce new growth at the location where you cut them.

After pruning, and with some good plant care, the newly cut stems should produce new flower spurs, resulting in additional flowers.

Common Problems With Hoya Carnosa

Common issues when growing and cultivating Hoya carnosa plants include browning leaves, wilting leaves, falling leaves, the absence of flowers, and possible pests and diseases.

Pests

Your wax plant is susceptible to various pests such as aphids, mealybugs, scale insects, and spider mites, which are sap-sucking insects.

Aphids are usually observed near the blooms, whilst mealybugs inhabit the leaves.

If you observe these pests, kill them immediately to prevent further plant damage.

Disease

Two common fungal infections infect wax plants; these fungi include botrytis blight. This causes rot on the plant, from the leaves to root rot.

Initial signs include wilting, dry or mushy black or brown stem lesions, and black or gray roots.

Other diseases include black sooty mold that grows on wax plant leaves. It’s caused by aphids, mealybugs, and other sap-sucking pests.

Sooty mold rarely threatens the wax plant’s vitality but can be removed by getting rid of the pests.

Neem oil and insecticidal soap are simple solutions to this problem.

Conclusion

Hoya carnosa is a tough tropical plant that is native to parts of Asia and Australia but is now grown all over the world. 

You can grow Hoya carnosa in pots indoors or outside. You can also grow it in the garden, as long as you have a warm, frost-free environment.

It’s evergreen and it just keeps growing. In the right environment, your plant will produce intriguingly beautiful, fragrant flowers.  

FAQ

Does Hoya Carnosa need full sun?

No, hoya carnosa plants do not need full sun. Hoya carnosa plants prefer indirect, mild to bright light. Some thrive with approximately two hours of direct sunshine in the morning or evening, but excessive sun exposure may burn or yellow their leaves.

How do I get my Hoya carnosa to bloom?

The key to getting Hoya carnosa plants to bloom is to expose them to bright, indirect light. Although hoya can live in low light, it will not blossom. In addition, fertilize the plant periodically to give it nutrients that will promote flowering.

How long do Hoya carnosa flowers last?

Typically, Hoya carnosa blooms are very durable and will last at least a week.

Is Hoya carnosa a succulent?

Yes, Hoya carnosa plants are succulents. These plants can retain water within their leaves, making them a type of succulent plant. Apart from their succulent leaves, hoya plants are different from other succulents as they are distinguished by their waxy flower clusters (also known as umbels).

References

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  • Smith, M. (2020). Hoyas as Houseplants. Pennsylvania State University Extension, College of Agricultural Sciences. URL: https://extension.psu.edu/hoyas-as-houseplants 
  • Kelt, J. (n.d.). Tri-color Wax Plant, Hoya carnosa. PlantTalk Colorado. Colorado State University Extension, Denver Botanic gardens, and the Green Industries of Colorado. URL: https://planttalk.colostate.edu/topics/houseplants/1344-tri-color-wax-plant-hoya-carnosa/
  • Henley, R.W., Chase, A.R., & Osborne, L.S. (1991). Wax Plant (Hoya) Production Guide. University of Florida, IFAS, Central Florida Research and Education Center. URL: https://mrec.ifas.ufl.edu/foliage/folnotes/waxplant.htmhttps://mrec.ifas.ufl.edu/foliage/folnotes/waxplant.htm 
  • North Carolina State Cooperative Extension. (n.d.). Hoya carnosa. NC State University Extension, Gardener Plant Toolbox. URL: https://plants.ces.ncsu.edu/plants/hoya-carnosa/

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