Gadenin日本語Get the appIt wants more light than a shade plant
Hoyas get sold alongside the low light houseplants and they will survive in that sort of position, which is how the reputation started. Surviving and flowering are different things. A hoya in a dim corner grows slowly, makes small pale leaves and never sets a bud.
Aim for a position that is bright for the whole day, with two or three hours of gentle direct sun at one end of it. Morning sun from an east aspect is ideal. Full midday sun through unshaded glass in summer bleaches the leaves in a couple of days, and those marks never go.
| Position | Light | What to expect |
|---|---|---|
| East window, unshaded | Morning sun then bright | The best all round position. Flowers reliably |
| South or west, behind a sheer curtain | Bright all day, diffused | Very good. Watch for heat build-up in summer |
| South or west, unshaded | Direct sun for hours | Leaves bleach and the compost bakes. Shade it |
| North window, at the glass | Bright, no direct sun | Healthy plant, flowers grudgingly if at all |
| More than six feet into the room | Dim | Slow, leggy growth. No flowers |
Thick-leaved hoyas take more sun than thin-leaved ones, and a plant with pale or variegated foliage burns sooner than a plain green one. Move any new plant into brighter light in stages over two weeks.
Temperature, and the cool spell that brings flowers
Hoyas are comfortable in ordinary room temperatures and grow best between 65 and 80F (18 to 27C). Growth slows below about 60F (15C) and cold damage starts around 50F (10C), showing as blackened patches on the leaves a few days after the event.
The useful exception is winter. A spell of six to eight weeks at 55 to 60F (13 to 16C) with very little water is what sets up the next season's flowering. A hoya kept warm and watered all winter in a heated living room stays green and healthy and produces far fewer buds.
- Find a cool bright room for winter An unheated bedroom, a landing or a porch that stays frost free will do. It needs to stay bright: cool and dark together just weakens the plant.
- Do not let it go below 50F Cool is the aim, cold is damage. If the room might drop below 50F (10C) on a hard night, move the plant off the windowsill for the night or bring it back into the warm.
- Keep it off drafts and radiators A hoya directly above a radiator dries and browns at the leaf edges. A hoya in the draft of an outside door drops buds. Both positions can be bright and still be wrong.
How to hang it or train it
The plant will do either. What you must not do is keep cutting it back to hold it neat, because you remove the growth that would have carried the flower spurs.
| Method | How it looks | Points to watch |
|---|---|---|
| Hanging pot | Runners trail down several feet | Hung high, the plant is often in poor light. Keep it near the glass |
| Hoop or trellis in the pot | Compact, stems wound round | Wind new growth on while it is soft. Old stems snap |
| Wires or hooks along a wall | Runners trained sideways from the window | Good use of a bright wall. Fix before the growth hardens |
| Left to sprawl on a shelf | Informal, stems everywhere | Stems touching other plants spread mealybugs |
When you wind a stem round a hoop, work with it in the afternoon when it is slightly less turgid, and never bend a section that carries a flower spur.
Once it is in bud, stop moving it
This is worth its own rule. A hoya carrying developing buds drops them if the light angle changes, and turning the pot a quarter turn is enough to do it. The bud stage lasts three to five weeks, which is a long time to leave a plant alone, but it is the difference between flowers and a pile of dropped pinheads.
That means the routine quarter turn people give houseplants to keep them even has to stop for the season, and it is a good argument for choosing the plant's position properly in early spring, before there is anything to lose.
Putting it outside for the summer
A hoya spends the summer outdoors very happily and the extra light often triggers a flush of flowers. The move has to be gradual and the return has to be early.
- Go out once nights are above 60F Wait until night temperatures are reliably above 60F (15C). There is nothing to gain from rushing it and cold nights on a wet pot cause rot.
- Two weeks in shade first Start in full shade under a porch or a tree and increase the light over a fortnight. A plant taken straight from a windowsill into open sun bleaches in one afternoon.
- Keep it out of the rain Continuous rain keeps the pot saturated, which is exactly the condition hoya roots cannot tolerate. Under an overhang is better than open sky.
- Come back in early Bring it in while nights are still around 60F (15C), not when they are dropping to 50F (10C). Wash the leaf undersides and the base of the pot first so you do not carry pests indoors.
Note down where the plant stood each summer and whether it flowered that year. Position is the variable that decides hoya flowering, and one season of records beats any amount of guessing.