How to Care for Hoya

Hoya, often known as the wax plant, is loved for its thick, waxy leaves and clusters of small, star-shaped flowers. The flowers can look almost porcelain-like, and many Hoya varieties are sweetly scented, with their fragrance often becoming stronger in the evening. Some even produce so much nectar that the flowers appear to glisten.

There are more than 500 species of Hoya, native to parts of Southeast Asia, India, Australia and the Pacific Islands. Most are epiphytes, which means they naturally grow on trees rather than in the ground. Their roots grip onto bark and other surfaces, with plenty of air around them.

Here's how to care for these beautiful plants.

How Much Light Does Hoya Need?

Hoya wants bright, indirect light, and it needs plenty of it to flower. A spot right by an east facing window is ideal, and a position near a south or west facing window with some protection from harsh midday sun works well too.

A couple of hours of gentle direct morning sun is genuinely beneficial and often the thing that tips a reluctant plant into flowering. Harsh afternoon sun through glass will scorch the leaves, so filter it with a net curtain. In low light a Hoya survives quite happily but grows slowly and will almost certainly never flower. If yours is healthy but has never bloomed, light is the first thing to change.

How Often Should You Water Hoya?

Let the compost dry out almost completely, then water thoroughly. In spring and summer that usually means once every one to two weeks, and in winter every three to four weeks.

Those thick, semi succulent leaves store water, so a Hoya is built to ride out dry spells. Overwatering is the main way people lose them. When you water, soak the pot until it runs from the drainage holes, then let it drain completely and never leave it standing in water. A chunky, free draining Hoya Mix with plenty of bark or perlite mimics the bark it would grow on in the wild and makes the whole thing far easier to get right. If in doubt, wait.

What Humidity Does Hoya Need?

Hoya prefers humidity of 50% to 60%, and it copes well with ordinary household air.

Coming from humid tropical forest, it responds to moist air with faster growth and glossier leaves, and higher humidity can help buds develop rather than dropping. It is not a fussy plant though, and those waxy leaves are well protected against drying out. If your home is very dry in winter, grouping plants together, standing the pot on a tray of damp pebbles or running a humidifier nearby will keep it comfortable.

What Temperature Does Hoya Need?

Hoya grows best between 18°C and 27°C and enjoys warmth in the growing season.

The lowest temperature it can withstand is around 10°C. Below that growth stops and the leaves can develop soft dark patches, particularly if the compost is damp at the same time. A slightly cooler winter rest, around 13°C to 16°C with much less water, actually encourages many Hoyas to flower the following summer. Keep it away from draughts and freezing window glass.

How Do You Propagate Hoya?

Hoya propagates readily from stem cuttings, and spring or early summer is the best time.

Take a cutting with at least two nodes, which are the points where leaves join the stem, and ideally two or three leaves. Cut just below the lower node with clean scissors and strip the leaves off that bottom node.

Stand the cutting in water, or push it into damp perlite or a chunky propagation mix, with the bare node covered. Keep it warm, bright and humid. Roots typically take three to six weeks, sometimes longer, so patience helps. Once roots are a few centimetres long, pot it into a free draining bark based mix and keep it on the dry side.

One important tip: never cut off the little woody spur that a flower cluster grew from. Hoyas flower from the same spur year after year, and removing it costs you all the future blooms from that point.

Why Are My Hoya Leaves Turning Yellow?

Overwatering is the leading cause. Yellow leaves that feel soft, especially low down on the plant, with compost that stays damp for days after watering, mean the roots are sitting too wet. Stop watering and let the compost dry right out. If the plant does not recover, slide it out and check the roots, cutting away anything brown and mushy before repotting into a chunkier, airier mix. Healthy stems can always be saved as cuttings.

Other explanations are worth checking. Yellow leaves that look bleached or washed out, often with dry brown patches, mean too much harsh direct sun. Yellowing with wrinkled, shrivelled leaves means the opposite of overwatering and needs a good soak. A sudden batch of yellow leaves after a cold spell points to chill damage. And one or two of the oldest leaves at the base of a long vine turning yellow and dropping is simply natural ageing.

If your real question is why it will not flower rather than why it is yellow, the answers are usually light, age and pot size. Hoyas need bright light, they need to reach a certain maturity, and they flower better when slightly pot bound, so resist repotting too often. Feed monthly in spring and summer with a balanced feed, and leave those old flower spurs alone.

Shop Hoya at House of Kojo

Want a plant that trails beautifully and rewards patience with scented flowers? Explore our Hoyas at House of Kojo, from the easy going classics to the rarer collector varieties.