Hoya, Porcelain Flower: Cultivation and Care

Botany and description

The Hoya originates from tropical and subtropical regions of Southeast Asia, India, Australia and the Pacific Islands. It is mainly found in humid forests, where it often grows as an epiphyte, clinging to tree trunks with its voluble stems. This ability to grow without soil, absorbing moisture from the air, explains its tolerance for light, well-drained soils when cultivated indoors.

The Hoya belongs to the botanical family Apocynaceae, like the periwinkle (Vinca minor) and oleander (Nerium oleander). This family also includes many tropical plants, some frequently grown indoors, such as Ceropegia, Adenium or Pachypodium. Most plants in this family share the characteristic of being toxic, containing alkaloids.

Hoyas were named by Robert Brown in 1810, a Scotsman who was among the first to introduce Hoyas into cultivation. He gave them this name in honour of his friend Thomas Hoy, head gardener to the Duke of Northumberland.

The genus Hoya comprises over 500 species, not counting the numerous hybrids and cultivars developed by enthusiasts of this fascinating plant. Hoyas thus offer exceptional diversity in terms of foliage, flowering and habit, allowing everyone to find the variety that suits them!

The Hoya forms long, flexible stems, which can be trailing (Hoya gracilis, Hoya linearis…), or climbing (like Hoya australis). It can thus be trained on a stake or arch, or grown in a hanging basket, from which its flexible stems will gracefully trail. Stem length varies by species, but can sometimes reach several metres under optimal growing conditions.

The foliage of the Hoya is one of its most appealing characteristics. Its leaves are generally thick and waxy. Their colour is most often a deep green, though there are many variegated varieties. Thus, in Hoya carnosa ‘Tricolor’ and Hoya burtoniae ‘Variegata’, young leaves are tinged red or pink, later becoming cream to yellow with green edges. In Hoya ‘Flamingo Dream’, this variegation is reversed, with dark green leaves edged in cream to pinkish-white. In Hoya callistophylla, leaves have a light green lamina, marbled with dark green veins, creating a superb contrast! Finally, some hoyas have silvery foliage, like the variety Hoya krohniana ‘Eskimo’.

Hoya leaves are most often lanceolate, but again some species stand out. Thus, Hoya wayetii has very fine, elongated leaves, Hoya retusa bears thread-like leaves, while Hoya kerrii has beautiful heart-shaped leaves (hence its nickname “heart plant”)! Its leaves are succulent, allowing it to store water and withstand drought. For this species, watering can therefore be less frequent than for other species! It also comes in a variegated form: Hoya kerrii ‘Variegata’, with yellow-edged leaves, visually enhancing their original shape. However, in terms of leaf shape, the most surprising is undoubtedly Hoya carnosa ‘Compacta’ with leaves curled in on themselves!

Hoya offers great diversity in foliage colours and shapes. Hoya carnosa ‘Tricolor’, Hoya lacunosa ‘Silver’, Hoya callistophylla, Hoya kerrii, Hoya retusa and Hoya carnosa ‘Compacta’

The Hoya is also highly prized for its spectacular flowering! It most often flowers in spring or summer, though this also depends on variety and growing conditions. It may flower several times a year! Its flowers form small stars grouped in umbels (sometimes up to 30 flowers per umbel), creating lovely little flower clusters. These have five waxy petals, with a small central crown (called the corona) made up of the pistil and stamens. The umbels are attached to the stem by a peduncle, which has the unique ability to bear flowers repeatedly! It is therefore important not to cut this peduncle once the flowers have faded.

Flower colour varies by species, but is most often in white or pink tones. Flowers may be white with a pink or red centre (like Hoya bella and Hoya kerrii), or entirely pink (Hoya ‘Flamingo Dream’), but also cream, beige, yellow, dark red, purple, even black…

The flowers emit an enchanting fragrance, often more intense in the evening (as in nature they are pollinated by nocturnal insects). The scent varies by species and growing conditions (heat generally promotes a stronger fragrance): it may evoke vanilla, cocoa, lily of the valley, almond…

The Hoya is particularly prized for its very delicate flowering. Left, flowers of Hoya bella, and right, those of Hoya kerrii

The best Hoya varieties

How to plant Hoya?

Where to Position the Wax Flower?

As a tropical plant, the Hoya prefers a warm and bright environment, without intense direct sunlight. It will thrive in temperatures between 18°C and 25°C. Ideally, place it near an east or west-facing window, where it will receive bright indirect light. Avoid direct afternoon sun, which could scorch its leaves, especially in delicate-leaved varieties. It will also appreciate being sheltered from cold draughts and temperature fluctuations. A humid room like a well-lit bathroom may suit certain species (e.g., Hoya linearis), but generally, the average humidity of a home is sufficient.

Place the Hoya in a bright spot, ideally near a window. Don’t hesitate to hang trailing varieties!

When to Plant Hoya?

Hoya can be planted or repotted in spring or early summer, when it enters active growth. This allows it to establish roots well before winter.

Avoid repotting in autumn or winter, as the plant slows its growth during this period and would take longer to adapt to its new pot.

How to Plant It?

Choosing the Pot:

• Opt for a terracotta pot rather than plastic, as it promotes better root aeration.
• Ensure it has drainage holes to prevent excess moisture, which can cause root rot.
• A slightly snug pot encourages flowering, so avoid choosing one that’s too large.

Ideal Substrate:

Hoya needs a light, well-draining substrate that isn’t too rich or compact. The substrate should allow good root aeration to prevent rot. You can use orchid compost mixed with perlite or create a homemade blend composed of light potting mix (about 40%), pine bark (20%), perlite (20%), and coconut fibre (20%).

Planting Steps:

1. Fill the pot with substrate, leaving enough space for the plant.
2. Gently remove the Hoya from its old pot, taking care not to damage its roots.
3. Place the plant in the pot and add substrate around the roots without compacting too much.
4. Water lightly to moisten the substrate without soaking the roots.

After planting, allow the Hoya to adjust to its new environment for a few days before watering again.

How to Care for the Porcelain Flower?

The Hoya is a fairly easy-to-care-for houseplant, but to encourage its growth and improve its chances of flowering, it’s essential to follow certain best practices regarding watering, fertilisation, and exposure.

Watering: How often and how to water the Hoya?

The Hoya is a plant that tolerates drought relatively well thanks to its thick leaves capable of storing water. However, improper watering can quickly become problematic. During the growth period, in spring and summer, we recommend watering it about once a week, while allowing the substrate to dry out between waterings. In autumn and winter, when the plant slows its growth, reduce watering to once every two or three weeks.

It’s important to use water at room temperature, preferably non-calcareous, such as rainwater or filtered water. Watering should be thorough, but excess water must be allowed to drain to avoid water stagnation, the main cause of root rot. Pay particular attention to signs of inappropriate watering: overwatering results in soft or yellowing leaves, while underwatering can cause wilting and wrinkled foliage.

Remember to water the Hoya regularly

Fertilisation: What fertiliser to use for the Hoya?

To stimulate growth and encourage abundant flowering, it’s recommended to fertilise the Hoya regularly. During the active growth period, in spring and summer, a liquid fertiliser for flowering plants, rich in phosphorus, can be applied every two to three weeks. An alternative is to use a balanced fertiliser, promoting both foliage development and flower production. However, in autumn and winter, it’s best to stop fertilising, as the plant enters dormancy and no longer needs additional nutrients.

The use of organic fertilisers, such as liquid compost or nettle manure, can also be beneficial, provided they are not overused. Excess fertiliser can indeed hinder flowering by promoting excessive foliage growth at the expense of flowers.

How to prune the Hoya?

The Hoya doesn’t require regular pruning, but some maintenance gestures help maintain a beautiful shape and stimulate flowering. It’s advisable to remove yellowed or damaged leaves to encourage the growth of new shoots. To control its growth, especially for climbing varieties, you can lightly prune overly long stems. However, a crucial rule to follow is to never cut the flower stems after flowering, as the plant has the unique characteristic of reflowering on the same peduncles year after year. Excessive pruning could therefore compromise future flowering.

When pruning is necessary, it should be done with clean, sharp secateurs to avoid unnecessary damage to the plant. A clean cut above a node encourages branching and the development of new stems, contributing to a denser and more harmonious habit.

The ideal environment: light, temperature, and humidity

The Hoya is a tropical plant that enjoys bright, indirect light. A spot near an east or west-facing window is ideal. If the plant is placed in direct sunlight, especially in a south-facing environment, it’s recommended to filter the light with a sheer curtain to prevent leaf burn. Conversely, insufficient light can slow its growth and prevent flowering.

Regarding temperature, the Hoya thrives ideally between 18 and 25°C and cannot tolerate temperatures below 10°C. It’s therefore important to keep it away from drafts and sudden temperature changes. Ambient humidity also plays a role in its well-being. Although it adapts to the dry air of our homes, a humidity level of 50 to 60% is optimal. In winter, when heating dries the air, it can be helpful to lightly mist its leaves or place a container of water nearby to increase humidity.

Your Hoya will appreciate occasional misting on its foliage!

Staking: how to guide its stems?

As the Hoya is a climbing or trailing plant depending on how it’s grown, it can be guided according to the desired effect. For structured growth, it can be trained on a hoop, trellis, or stake. This technique helps direct its stems and encourages more uniform flowering. Conversely, if a more natural look is preferred, it can be left to grow in a hanging basket, where its long stems will form a beautiful cascading display.

When to repot the Hoya?

The Hoya doesn’t need frequent repotting. Repotting every 2 to 3 years is sufficient, unless the roots are coming out of the pot or the substrate is depleted. Each time, choose a pot slightly larger than the previous one.

Proper repotting promotes healthy growth and helps eliminate a substrate that has become too compact or nutrient-poor.

→ Read our detailed advice in How to repot a houseplant?

Diseases and parasitic pests of Hoya

Although the Hoya is a robust plant and relatively resistant to diseases, it can nevertheless be prone to certain problems when grown in unsuitable conditions. Excess moisture, poor air circulation or parasitic infestation can compromise its growth and flowering. It is therefore essential to recognise the signs of diseases and infestations in order to act quickly and preserve the health of the plant.

Common Hoya Diseases

One of the most common problems with Hoya is root rot, usually caused by overwatering and poor substrate drainage. When the roots are constantly wet, they begin to necrotise and can no longer absorb the nutrients the plant needs. This problem manifests itself through yellowing leaves, general wilting and sometimes an unpleasant smell coming from the soil. To avoid this situation, it is essential to let the substrate dry out between waterings and to use a well-draining substrate as well as a pot with drainage holes at the bottom to allow excess water to escape. If rot is already present, it is advisable to repot the plant by removing the damaged roots and using a fresh, aerated substrate.

Excess moisture can lead to the appearance of fungi on the surface of the substrate and yellowing of the foliage.

Hoya can also be affected by powdery mildew, a fungus that develops due to excessive moisture and poor air circulation. This disease is recognisable by a whitish deposit on the leaves, which may then become deformed and fall prematurely. To prevent its appearance, it is recommended to avoid wetting the foliage when watering and to ventilate the room where the plant is located regularly. In case of an attack, a treatment based on sulphur or baking soda diluted in water can be applied to limit the spread of the fungus.

Hoya Pests

Several harmful insects can attack Hoya, including mealybugs, aphids and spider mites. Mealybugs are particularly dreaded parasites, as they attach themselves to the stems and under the leaves, where they form small cottony clusters. They weaken the plant by sucking its sap, causing slowed growth and yellowing of the foliage. To get rid of them, you can use a cotton pad soaked in 70° alcohol to clean infested areas or apply a treatment based on black soap diluted in water.

Aphids, although less common, can also colonise young shoots and weaken the plant by sucking its sap. They often leave behind a sticky substance called honeydew, which promotes the development of sooty mould, a blackish fungus that disfigures the foliage and hinders photosynthesis. To get rid of them, spray black soap on infested areas (15 to 30 g of black soap diluted in one litre of water).

Finally, spider mites are microscopic mites that usually appear when the air is too dry. Their presence is indicated by a gradual yellowing of the leaves, accompanied by fine webs on the stems and under the foliage. To prevent their proliferation, it is recommended to increase ambient humidity by lightly misting the plant and avoiding environments that are too hot and dry. If the infestation is advanced, a treatment based on neem oil or an organic miticide can be applied to eradicate these parasites.

For more advice, feel free to consult our fact sheets on mealybugs, aphids and spider mites.

How to propagate Hoya?

The Hoya is a plant that can be easily propagated by cuttings, a simple and effective method to obtain new plants from an existing stem. This technique not only allows you to faithfully reproduce a variety you appreciate but also to exchange cuttings with other enthusiasts. Propagation by cuttings is the most common method, but other techniques, such as layering, can also be used to successfully propagate the Hoya.

Propagating Hoya by cuttings

Propagation by cuttings is the simplest and quickest way to multiply the Hoya. It is best practised in spring or summer, when the plant is in full growth. To succeed with cuttings, it is important to choose a healthy and vigorous stem, bearing at least two to three nodes.

• Cut a stem section of about 10 to 15 cm with clean and disinfected secateurs. It is recommended to make the cut just below a node, as this is where roots are most likely to form.
• Remove the lower leaves to prevent them from soaking in water or the substrate and rotting.

Once the cutting is prepared, it can be rooted in water or directly in a light substrate. Rooting in water is a very popular method, as it allows you to easily observe the emergence of roots:

• Place the stem in a glass of water at room temperature, ensuring that at least one node is submerged.
• The water should be changed regularly to prevent the proliferation of bacteria.
• After a few weeks, roots will begin to form. Once they reach about 3 to 5 cm, transplant the cutting into a pot with a well-draining substrate.

You can also plant the stems directly into pots filled with substrate:

• Plant the cutting directly in a mixture of light potting soil, perlite, and pine bark.
• Water moderately to maintain consistent moisture without overwatering.
• To encourage rooting, place the cutting under a cloche or in a transparent plastic bag to create a greenhouse effect that maintains good humidity.
• After three to four weeks, the first roots will appear, and the plant will begin to develop new shoots.

A Hoya cutting

Layering the Hoya

Layering is another effective technique for propagating the Hoya, particularly for varieties with long and flexible stems. This method involves encouraging a stem to produce roots while still attached to the mother plant.

• Select a vigorous stem and lay it over a pot filled with substrate without detaching it from the plant.
• At the spot where you want roots to appear, lightly incise the stem to stimulate root formation.
• Cover this area with substrate and maintain regular moisture.
• After a few weeks, new roots will form at the layered section.
• Once well-rooted, separate the new plant from the mother plant and transplant it into an individual pot.

Layering a Hoya

How to showcase the Hoya and which plants to pair it with?

Hoya pairs beautifully with other tropical plants that enjoy bright light and a relatively humid atmosphere. To create a jungle vibe in your home, combine it with other lush-leaved plants like Monsteras, prized for their large, beautifully divided leaves. Also consider Alocasias, Calatheas, Chlorophytums and Pothos. You can also pair it with orchids, which share similar requirements in terms of substrate and moderate watering.

If grown in a hanging basket, Hoya can be combined with other trailing plants like Rhipsalis, Ceropegia or Dischidia, creating a very aesthetic cascading effect. These plants share the same need for well-drained substrate and moderate watering. For an urban jungle look, you can also combine it with Boston Ferns (Nephrolepis exaltata), which will add a touch of lightness with their delicate, finely divided foliage.

Don’t hesitate to mix different Hoya varieties, especially as they offer great diversity in foliage and flowering! For contrast, you could pair a Hoya carnosa ‘Krimson Queen’, with white and pink variegated leaves, with a Hoya obovata, featuring rounded leaves speckled with silver. Similarly, a Hoya linearis, with its long pendulous stems, creates beautiful balance alongside a Hoya compacta, whose twisted leaves add original texture.

Feel free to combine different Hoya varieties together, accompanied by other decorative-leaved houseplants like Colocasias

Playing with supports and containers

Hoya is a plant that adapts to various decorative styles thanks to its climbing or trailing habit. For a stunning effect, you can display a Hoya with long trailing stems, such as Hoya gracilis or Hoya krohniana, in a ceramic pot hung with macramé. On a wall shelf, a potted Hoya placed on a piece of driftwood creates a natural, minimalist look.

Climbing Hoyas like Hoya australis can be trained onto a metal hoop, forming an elegant, refined plant structure. A bamboo trellis or wooden ladder also helps guide the stems while adding decorative flair to your space.

You can train Hoya stems to climb a support, or let them trail if grown in a hanging basket!