Hoya callistophylla is a flowering tropical plant native to Southeast Asia and parts of Australia and New Zealand.

In its natural habitat, it usually grows on trees, but it also makes a very showy potted indoor plant.

This guide reveals all the care and grow tips you need to introduce it to your home!

What is Hoya callistophylla?

Hoyas are often called ‘wax plants’ due to their waxy leaves and flowers. In Hoya callistophylla, the leaves are oval-shaped, vivid green, with dark green nerves making a unique pattern on the surface. Its main feature, however, is the flowers. Like all Hoyas, it produces umbrella-shaped blooms. The flowers are usually white or pale yellow, with dark red edges and a pleasant fragrance.

Hoya callistophylla can develop vines that are up to 16 feet (almost 5 meters) long when grown indoors. Luckily, this evergreen succulent is a slow grower. With the right care tips, it can thrive for many years, producing lots of gorgeous flowers in the process.

How to care for Hoya callistophylla

Let’s take a look at some key features and tips for caring for this plant:

  • Hoya callistophylla is a succulent.
  • Given that it’s also an epiphyte, it needs loose, well-draining soil and moderate watering.
  • It can be particularly sensitive to rot, which can affect both roots and stems, and leaves.
  • Only mature Hoya plants flower, so it may take several years before the plant blooms.

– Light requirements

Hoya callistophylla needs bright, indirect light to grow. Although this plant is from the succulent family, direct sunlight will scorch the leaves, gradually causing them to wilt.

If you have a room with windows facing east, this Hoya can withstand the early morning sun for a few hours without the leaves getting burned. Otherwise, place it in a room with western or southern exposure, at least 2 feet (60 cm) away from the window. You can also use sheer curtains to reduce the impact of direct sun on Hoya callistophylla leaves.

Light has a major impact on whether your Hoya callistophylla will flower or not. During spring and summer, make sure that your plant receives around 8 hours of dappled sunlight each day. If the plant gets too little light, it will delay its flowering season, or you might even notice that your Hoya is not blooming at all.

– Temperature range

Hoya callistophylla is an indoor plant that needs a temperature range between 65 °F and 80 °F (18 °C to 27 °C). If the room is humid enough, it can also tolerate temperatures as high as 86 °F (30 °C). However, its health will start deteriorating if temperatures hit 50 °F (10 °C) and stay that low for long periods.

– Water requirements

Like all succulents, Hoya callistophylla is deathly sensitive to overwatering. On average, you should water it once a week during spring and summer, then cut back to watering your Hoya callistophylla once every two weeks in autumn and winter.

Always allow the soil to dry out a bit in between waterings. Use your finger to check that the top 2 inches (5 cm) are dry to the touch, then give your Hoya callistophylla a good soak. Water the plant at the base, and avoid splashing the leaves, as this can cause fungal problems. If the leaves are starting to turn yellow, that’s a sign of too much water or even root rot.

– Humidity

Hoya callistophylla should thrive in the 40 percent to 60 percent humidity range that most homes fall under. However, a humidity boost will stimulate abundant growth during spring and summer. If you can, try to aim for a range of 50 percent to 70 percent.

The best way to increase humidity around your Hoya is by placing it on a pebble tray. You can also use a humidifier or group it with other plants to create a microclimate with higher moisture levels. Avoid misting the leaves, as this will cause brown spots and fungal problems. If you notice that the leaves are wet, especially after watering the plant, be sure to dry them off.

– Fertilizers

Hoya callistophylla only needs fertilizers once a month, from spring through to the end of summer. The plant enters a dormancy period at the end of its growing season, so avoid feeding it during that time. Use an organic, liquid fertilizer that’s rich in both nitrogen and phosphorus. Hoya callistophylla is a flowering plant, and the phosphorus boost will stimulate the production of healthy blooms.

– Best soil

Use a potting mix that is well-draining and aerated. Hoya callistophylla does not like being waterlogged, so good drainage is the most important feature you’re looking for. You can create the best soil for Hoya callistophylla by combining equal parts peat, perlite, and orchid soil mix. These should provide a well-draining substrate that’s also slightly acidic, which is just what this Hoya needs.

– When to repot

Hoya callistophylla has a slow growth rate, and it can take many years for the plant to reach at least 3 feet (90 cm) in length. It also goes dormant during winter, when all growth stops. As such, you should only need to repot this Hoya plant once every two years.

Repot your Hoya callistophylla in a container that’s around 2 inches (5 cm) wider than the previous one. For this plant, we recommend using clay pots rather than plastic ones.
Clay is a porous material, allowing the air and water to circulate better around the root ball.

They will enable the soil to dry quicker, which is an essential feature when using the soak and dry method to water your Hoya. Clay or terracotta pots also help reduce the risk of root rot or fungal problems with your plant.

– Pruning

Hoya callistophylla can grow vines that are up to 10 feet (3 meters) in length. Depending on your home setup, you can trail these vines along the walls using hooks or even encourage them to climb on a trellis.

If you wish to keep your Hoya a bit more contained, you can trim some of the longer vines in spring or summer. Avoid removing more than one-third of the plant each year. The plant will produce new growth from the sections that have been cut, which also results in more flowering stems.

When pruning your Hoya callistophylla, take care not to remove the woody peduncles growing at the ends of some vines. Those peduncles are the spot on the stem from which flowers will grow. If you remove them, there will be fewer blooms that year.

How to propagate Hoya callistophylla

There are three ways to propagate your Hoya callistophylla: stem cuttings, leaf cuttings, and air layering.

The best time to propagate Hoya is in spring and summer, during the plant’s growing season. As your Hoya matures, you will notice that some stems become woody, while the young ones are typically ‘green.’ Only use young stem cuttings for propagation, as they have a better chance of developing roots.

– Propagating through stem cuttings

Here’s our step-by-step guide on how to propagate Hoya callistophylla through stem cuttings:

  1. Pick a stem that is green or semi-green, without any wooden peduncles attached.
  2. Use a sharp, sterilized knife to cut the stem about 1 inch (2.5 cm) below the leaf node. Each cutting should be around 5 inches (13 cm) long and have at least two leaves.
  3. For long vines, you can cut them in several sections below the root node. On average, it’s best to propagate 2 or 3 cuttings at a time and plant them in the same pot so that the new plant will have a fuller look.
  4. Place the cutting in a well-draining potting mix, and give it a good watering.
  5. To minimize the chance of stem rot during propagation, you can apply a fungicide solution to the soil. Also, using a rooting hormone can speed up the rooting process.
  6. Keep your pot with cuttings in a room that gets plenty of bright, indirect light. Make sure that temperatures don’t drop below 65 °F (18 °C). Water the plant regularly, but avoid soaking the soil.
  7. Hoya cuttings will root faster if enough humidity is available. To give them a boost, wrap a transparent plastic bag around the pot.
  8. Be patient. Hoya callistophylla cuttings can take up to a month to develop roots and another 2 to 3 months before the plant has a sufficiently developed root system.

– Propagating through leaf cuttings

Following more or less the same process as stem cuttings, you can use this method if you have a Hoya plant that doesn’t have too many long stems to work with. It’s worth mentioning that plants propagated this way will take much longer to develop any growth.

In some cases, your Hoya leaf cutting can take up to a year before it grows a stem and new leaves.

To propagate Hoyas through leaves, cut the leaf stem at a slight angle. Place the cutting in a pot filled with one part potting mix and one part perlite. The stem should be in the soil, but the leaf itself should be pointing upwards to minimize the risk of moisture damage during watering. Water the soil, and wrap a plastic bag around the pot to help retain humidity. On average, the leaf will develop roots in 6 weeks.

– Air layering

If you have a Hoya callistophylla with very long stems but a sparse look, you can also use air layering as a propagation method. Air layering is a propagation technique in which the stems are still attached to the parent plant. This method works on many hanging plants with aerial roots, and it’s a great way to give your Hoya a bushier appearance.

Air layering is a simple, non-invasive way to propagate Hoya callistophylla. Start by identifying the aerial roots: they are small bumps forming a ridge along the stem. You can either lay this section of the stem on the same pot’s soil or a separate pot. Remember not to cut the stem! Use pins or small hooks to keep the stem down and pile a bit of soil around it without covering it. Continue to care for the mother plant as usual, and the new roots will develop in a few weeks.

Can you grow Hoya callistophylla from seeds?

In theory, yes, you can grow Hoya callistophylla from seeds. However, Hoya callistophylla seeds can be a bit tricky to find. This is because pollinating these flowers is very difficult, and the seed pods take months to mature. Also, the seeds have a short lifespan, and once they dry out, germinating them will be almost impossible. Hoya seeds are very small and look very similar to dandelion seeds. For the best chance of germination, only use freshly harvested seeds.

Use a container filled with equal parts bark, perlite, and some peat at the top. Water the soil well, then spread the seeds on top and mist them with a spray pump. Cover the pot with a plastic bag to help retain humidity. Keep the soil moist, and make sure that temperatures don’t drop below 65 °F (18 °C). The Hoya seeds should germinate in a few weeks.

Hoya callistophylla problems

Hoya callistophylla is relatively resistant to pests and diseases. The most common problems it encounters are caused by a poor watering schedule or by incorrect lighting.

1. Root rot

Suppose you notice that the leaves on your Hoya callistophylla are developing soft, brown spots. In that case, that’s usually a sign of root rot or other fungal problems caused by too much water. Try to cut back on watering until the top inch of the soil feels dry to the touch. Also, make sure that the soil mix is well-draining and that the pot has a drainage hole at the bottom.

2. Leaf discoloration

Leaf discoloration on your Hoya callistophylla typically has two causes. Leaves will turn yellow and drop if the plant suffers from water stress, whether it’s too much or too little water. If the leaves are starting to turn red, that’s a sign of too much light exposure. Move the Hoya further away from the window so that the sun won’t scorch the leaves.

3. Pests

Some pests that might attack your Hoya callistophylla are spider mites, scale, and mealybugs. Wipe the leaves with water and isopropyl alcohol solution once every 4 to 7 days to remove them. Repeat the treatment for a month until all signs of the infestation are gone.

Flowering Hoyas, especially those kept outdoors during the warm season, can suffer from aphid attacks. In these cases, wipe the stems and flowering peduncles with a damp cloth, and try to remove as many of them as you can.

Avoid splashing water on the leaves or keeping them too wet, as this can lead to fungal problems. Once the adults are removed, use a clean piece of cloth and some insecticidal soap solution to wipe the infected areas. This should prevent further attacks.

4. Not flowering

Hoya callistophylla only produces flowers when it reaches maturity. On average, your plant will need to be at least five years old before it blooms. So if you’re wondering why your Hoya is not flowering, the most straightforward answer is that it might just be too young.

However, flowering issues can also be caused by stress. Suppose your Hoya callistophylla isn’t receiving enough light and fertilizers. In that case, if the humidity is too low, or if pests attack it, it will preserve its energy by not blooming.

Try giving the plant a couple of hours of direct sun in the morning. Use fertilizers that are rich in phosphorus, which promotes flower growth. If the blooms fall off before they have opened, your Hoya callistophylla is probably under watered. Also, if your Hoya has been sitting in the same pot for over two years, check the roots and repot it to a bigger container.

Conclusion

Hoya callistophylla is a stunning plant that looks superb in any home. Growing it takes time and patience, but it’s worth the efforts.

Let’s go over the basics:

  • Too much water is the most common cause of problems with Hoya callistophylla, so take care not to overdo it;
  • In the same vein, a well-draining soil mix will keep fungal problems like root rot at bay;
  • It takes a few years before you’ll see flowers on your Hoya callistophylla, but the leaves more than make up for that!

With this guide, you have all the care and growing information you need to grow Hoya callistophylla at home, so why not give it a go!

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