Hoya Carnosa Care: Growing Wax Plants

By Andrea Beck | Updated: June 11, 2023

hoya-carnosa-featured
Scientific name

Hoya carnosa

Common name

Wax Plant

Origin

Eastern Asia and Australia

Checked by Jennifer Schutter, Certified Master Gardener

Wax Plant

Water

When top half of soil is dry

Light

Bright indirect light

Soil

Well-draining mix of potting soil, perlite, and orchid bark

Placement

Near east- or west-facing windows

Difficulty

Easy

Fertilizer

Optional during growing season

Light

Bright indirect light

Difficulty

Easy

Fertilizer

Optional during growing season

If you’ve been on the lookout for a low-maintenance yet stunning addition to your houseplant collection, the wax plant (Hoya carnosa) might just be your new best friend.

With its intriguing, waxy leaves and a flair for draping gracefully over the edges of pots or hanging baskets, this hoya variety is sure to turn heads and spark conversations.

But don’t worry, we’re not just going to leave you hanging with a vision of wax plant grandeur.

In this article, we’ll introduce you to everything you need to know about Hoya carnosa care, from propagation and its ideal conditions, to how to deal with the common issues!

Hoya Carnosa Plant Care Guide

History, Habitat, and Characteristics

Hoya carnosa (wax plant) as a native of Eastern Asia — specifically Japan, China, and Taiwan — has charmed indoor gardeners across the globe with its unique blend of beauty and resilience.

Why the name wax plant, you ask? Well, the plant’s thick, green, succulent-like leaves possess a glossy, waxy texture that gives it its signature appearance.

But it’s not just the foliage that catches the eye. Hoya carnosa is particularly admired for its stunning blooms, which often emit a delightful fragrance that enchants plant lovers like a botanical siren song.

While some of its relatives might be a tad finicky, this plant is more easygoing, making it an excellent choice for beginners. It’s a prolific grower and can tolerate a degree of neglect that other hoya plants simply can’t handle. A low-maintenance star in the hoya universe!

You won’t have to embark on a wild plant hunt to find Hoya carnosa. Its widespread popularity makes it a common sight in plant shops and garden centers. As a result, it’s typically one of the first hoya plants people bring home.

Fun fact: Hoya carnosa’s beautiful flowers don’t just smell good — they also produce a sweet nectar that can sometimes be seen dripping from the blossom clusters.

Light

Hoya carnosa, or the porcelain flower, as it’s also known, thrives in an environment that closely resembles its native habitat, where it experiences bright indirect light with occasional exposure to full sun. An east- or west-facing window is ideal. For south-facing windows, place it a few feet away from the window to avoid the harsh afternoon sun.

When a Hoya carnosa receives too much direct sun, the foliage may appear faded and bleached, even developing small holes. If you observe these symptoms, move the hoya plant to a spot with filtered bright light, or add a sheer curtain over the window to soften the sunlight.

Conversely, a Hoya carnosa that is not getting enough light may display slow or leggy growth, with leaves stretching toward the closest light source. You also might be less likely to see your hoya flower. To remedy this, adjust the plant’s position to receive more balanced light, or consider using an artificial light source.

Water

You’ll want to get the watering just right if you want your Hoya carnosa to thrive and produce flowers. Hoyas don’t like consistently wet soil, so you need to monitor your plant regularly.

Stick your finger into the potting soil, and when the top two inches have gone dry, give it a drink. Water enough that it flows from the drainage holes, but allow the pot to drain completely before placing it back on the drip tray.

Hoyas tend to go dormant in the winter, slowing their growth and requiring less water. You’ll find that you need to water it more in the summer and less in the winter. Keep a close eye on the soil during colder weather and let it dry out more than you would in the summer.

Overwatering won’t result in a healthy Hoya carnosa, but neither will underwatering. Signs that your hoya isn’t getting enough water include shriveled and yellowing or browning leaves. If the leaves are falling off, on the other hand, or the stems and petioles appear mushy, you’re likely overwatering. Let the soil dry out more between waterings.

Temperature and Humidity

Hoya carnosa thrives in the range of 64-82°F (18-28°C), with a minimum of 59°F (15°C) at night. It’s essential to protect them from cold drafts, drafty doors or windows, and air vents, which can negatively affect your plant’s health, causing leaves to curl, droop, or fall off.

As for humidity, hoyas are fairly versatile. Hoya plants appreciate higher humidity levels but can adapt to standard household conditions with a humidity of 40%-60%. Keep an eye on the plant’s leaves — if the tips turn brown or curl, the humidity might be too low, whereas mold or rot indicates too much humidity.

To increase humidity:

  • Position your hoya plant on a tray filled with water and pebbles, which allows the water to evaporate and raise the surrounding humidity.
  • Group your hoya plant with other plants so they can share moisture through a process known as transpiration.
  • Run a humidifier near your plants to maintain constant humidity levels.

Soil and Planting

Hoya carnosa plants aren’t fast growers and won’t need to be repotted frequently. Likewise, they don’t like their roots being bothered, so repot with care.

Hoyas don’t mind being a bit root bound, and will certainly prefer it to being placed in too much soil, so don’t increase your pot size by more than a couple of inches. A well-draining mix, such as a standard houseplant soil or cactus mix, is perfect.

To increase drainage, you can add:

  • Perlite or pumice. These ingredients prevent compaction and promote drainage and aeration, allowing the plant’s root ball to breathe easily.
  • Orchid bark. Bark chips maintain the right balance of moisture and provide additional aeration, preventing the soil from becoming soggy.
  • Charcoal. Horticultural charcoal keeps the soil fresh and healthy by absorbing impurities, while also improving drainage and aeration.
  • Coconut coir. Coco coir is a well-draining but moisture-retentive and eco-friendly alternative to peat moss.
  • LECA. LECA, or light expanded clay aggregate, is a popular alternative because it retains moisture well without ever becoming waterlogged. Some people add it to the bottom of all their pots.

In spring and summer, fertilize your hoya with either synthetic or organic fertilizers. Use synthetic fertilizer monthly at half the suggested rate or apply organic fertilizer every time you water.

If you notice thinner leaves, poor growth, or leaf drop, over-fertilization may be the culprit. In that case, reduce the amount and frequency of fertilizer, and flush the potting medium with water to remove excess salts.

Propagation

Propagating Hoya carnosa plants is an excellent opportunity to share these beautiful plants with friends and family.

Propagate Hoya carnosa plants using stem cuttings:

  1. Get your materials ready: First, gather a pair of sterilized gardening shears, a small container with drainage holes, and some potting mix (you can throw in any of the materials in the “Soil and Planting” section as well) for rooting.
  2. Cut a stem cutting: With your sterilized shears, snip a 4-6 inch section of the stem just below a leaf node. Make sure there are a few healthy leaves at the top of the cutting and that the stem is mature and healthy, with visible adventitious (growing in a good spot!) roots growing along its thin vines (these may appear as small bumps).
  3. Remove lower leaves: Gently pluck off any leaves from the bottom part of the stem. This prevents the leaves from decaying in the rooting medium.
  4. Place cutting in rooting medium: If you’re using water, fill a small container with filtered water and pop the cutting in. For potting mix, dampen the medium and place the cutting into it, making sure the adventitious roots touch the medium.
  5. Boost humidity (optional): To keep the humidity up during the rooting process, you can cover the cutting with a plastic bag or enclosure. This creates a more suitable environment for root growth, especially in dry or air-conditioned spaces.
  6. Keep an eye on the cutting: Place your cutting in a warm, bright spot with indirect light. If you’re using water, change it every 2-3 days. For potting medium, make sure it stays moist but not soaking wet.
  7. Watch for roots to form: Give it a few weeks, and you should see new roots sprouting from the adventitious roots on the stem cutting. Once they’re at least an inch long and well-established, your hoya cutting is ready to be potted in an appropriate potting mix.

Common Issues

Hoya plant care is typically pretty easy, but like most plants, they might encounter some issues along the way.

Not Blooming

Hoya flowers are truly a sight to behold. To encourage yours to bloom, follow these tips:

  • Provide proper lighting. Ensure your plant is receiving the right amount of bright, indirect light. Inadequate lighting can hinder blooming, so adjust the plant’s position as needed or consider using artificial light sources.
  • Maintain optimal temperature. Hoya carnosa prefers temperatures between 60-85°F (15-29° C). Keep your plant away from drafts and sudden temperature changes.
  • Be mindful of watering. Wax plants prefer to dry out slightly between waterings. Overwatering can cause root rot and prevent blooming, so make sure to use well-draining soil and allow the top inch of soil to dry out before watering again.
  • Feed your plant. During the spring and summer, feed your Hoya carnosa plant with a balanced, water-soluble fertilizer every 4-6 weeks. Proper nutrition will help promote blooming.
  • Prune your plant. Flowers bloom from new growth, and pruning promotes growth. So it stands to reason that pruning will result in flowers! When you prune, remove only a third of each vine, and free two birds with one key by propagating what you remove.
  • Be patient. Sometimes, a porcelain flower may take a few years to mature and start blooming. Be patient and continue providing proper care, and your perseverance will be rewarded!

Pests and Diseases

Mealybugs

These little critters are small, white, and cotton-like, often hiding in the nooks of your hoya plant’s leaves and stems. They feed on your plant’s sap, which can weaken it over time. To spot them, look for tiny white cottony masses on the leaves and stems of your Hoya carnosa.

When faced with mealybugs or any other common pest, here’s what you do.

First, take a cotton swab dipped in rubbing alcohol and gently remove the bugs. If the infestation persists, apply a natural insecticidal soap or neem oil (just remember to follow the label instructions for proper use).

To prevent future infestations, maintain clean leaves by wiping them regularly with a microfiber cloth or a damp sponge. This helps prevent dust buildup, which attracts pests and blocks light absorption.

Root Rot

Root rot is an all-too-common problem among indoor plants, and the hoya plant is no exception. It’s usually caused by overwatering or poor drainage, and sadly, it often remains unnoticed until it’s too late. Telltale signs include yellowing leaves, wilting, and a persistent foul smell from the soil.

To save your hoya plant, act swiftly: Remove the plant from its pot and inspect the roots. Healthy roots are light in color and firm, while rotted roots appear dark, slimy, and mushy. Trim away the affected roots using sterilized scissors, rinse away the soggy soil from the healthy roots, and let them air dry for a couple of hours.

Repot your Hoya carnosa in fresh, well-draining soil. Improve drainage by adding perlite, pumice, or LECA to your potting mix, and ensure the pot you’re using has drainage holes.

To avoid root rot in the future, water your hoya plant only when the top few inches of soil are dry. And don’t forget to empty the saucer under the pot after watering!

Conclusion

That’s a wrap on our Hoya carnosa care guide! You’re now equipped with the knowledge and tips to care for your plant, ensuring it thrives in your indoor garden.

Hoya carnosa care summary:

  • Provide bright, indirect sunlight to encourage healthy growth and flowering.
  • Maintain consistent temperatures between 64-82° F (18-28° C) and humidity levels of 40%-60%.
  • A well-draining soil mix, including perlite or pumice, orchid bark, and charcoal, is essential for a healthy root system.

We hope this comprehensive guide has helped you understand and appreciate the unique charm of the wax plant. If you have any questions, don’t hesitate to reach out to us.

And, as always, happy gardening, and take care!

FAQ

Should I trim my Hoya carnosa?

Yes, trimming your Hoya carnosa can benefit its overall health and appearance. Regular pruning helps maintain the plant’s shape, encourages bushier growth and flowers, and removes any unwanted or unhealthy stems. To trim your plant, follow these simple tips:

  • Trim your wax plant in early spring, just before the growing season begins. This allows the plant to recover quickly and focus its energy on new growth.
  • Use clean, sharp pruning shears or scissors to ensure a clean cut and minimize the risk of spreading diseases.
  • Look for long, leggy stems or any parts that appear unhealthy or overcrowded. You can also remove any stems that are growing in undesirable directions.
  • Remove only 1/3 of the stems and cut at a 45-degree angle, about 1/4-inch above a leaf node. This encourages new growth from the remaining node.

Sources

master-gardener-headshot
Our Expert
Jennifer Schutter

Jennifer Schutter is a certified master gardener with over 14 years of gardening experience. Her expertise is in indoor plant propagation and home ecology.