Wax plant

The wax plant grows through the forests of eastern Asia and Australia, climbing trunks and rocks with roots that grip bark rather than sink into soil. The leaves are thick and waxy, the stems are wiry, and the flowers are the reason people keep it: tight balls of small star shaped blooms, each one looking as though it was cast in porcelain, that open in the evening and smell strongly of honey. It is an easy plant to keep alive and a slightly particular one to bring into flower, and everything about the second half comes down to leaving it alone.

Light

Bright indirect light with an hour or two of gentle direct sun, morning or late afternoon, is what makes a hoya flower. An east window is close to ideal. In a dim room the plant grows perfectly happily, makes long stems and thick leaves, and never blooms, which is by far the most common complaint about it.

Water

Let the compost dry most of the way through, then soak it thoroughly and let it drain. In a warm room that is about every ten days in summer and every eighteen in winter. Lift the pot to judge it rather than watching the surface.

Those thick leaves are water stores. A hoya that has gone a fortnight too long wrinkles slightly and recovers from one watering; a hoya kept damp loses its roots. Wrinkled leaves on damp compost are the warning sign that the roots have already gone, and they need a different response from wrinkled leaves on dry compost, so always feel the pot before reaching for the watering can.

The mix and the pot

In the wild the roots run in bark and leaf litter with air all round them, and they suffocate in ordinary compost. A mix of orchid bark with a little compost and perlite is worth making up and is often the whole fix for a hoya that yellows from the bottom.

Leave it potbound. A hoya flowers when its roots are crowded, and repotting into a generous pot reliably delays flowering by a year or more. Every third year at most, one size up.

Flowering, and the one rule

Flowers come from short woody spurs on the stems. Each spur is used again, year after year, and often for a decade. Cutting the old flower stalks off, which looks like tidying, removes next season’s flowers, and this is the single most common way people stop their hoya blooming. Pull the faded blooms away if you want to, and leave the stalk exactly where it is.

A hoya usually needs to be two or three years old before it flowers at all. Once it starts, it flowers repeatedly through spring and summer, and each cluster drips a sticky, sweet nectar that is entirely normal and washes off.

Pruning and propagation

Prune as little as possible, and never cut a flowering spur. Long bare stems with no leaves are not a fault; they are the plant searching for something to climb, and they leaf up once they find a support. Give it a hoop or a trellis and it will use it.

Cuttings root easily. Take a piece with two or three pairs of leaves and at least one node, and stand it in water or push it into damp bark mix. Roots appear within a few weeks. A stem pegged down onto the compost roots at the node without being cut at all.

Ailments

No flowers is light, age, pot size or a cut spur. Yellow lower leaves mean the mix holds too much water. Wrinkled leaves need a finger in the compost first. Stickiness under a flowering plant is nectar and harmless; stickiness with no flowers means mealybugs. The ledger below has the rest.