Hoya care: light, water and how to get it to flower
A hoya grows well in bright, indirect light, in a chunky, fast-draining mix that dries out between waterings. Light decides whether it flowers, and overwatering is what rots it. This page covers placement, watering, compost, getting it to flower, climbing or trailing, which hoya to buy and pet safety.
- Bright, indirect light, near a window but out of hot summer sun.
- Let the mix dry out between waterings, and water less from October to February.
- Never cut off the flower spurs: new flowers come from the same ones.
What a hoya is
Hoya is a genus of over 500 species, Clemson says, in the dogbane family with the string of hearts. Iowa State says hoyas come from tropical and subtropical Asia, Australia and nearby islands, where they grow as epiphytes on tree branches. The one this page leads with, Hoya carnosa, the wax plant, comes from Southeast Asia, Japan and Taiwan according to NC State, and has thick, waxy leaves 8 to 15 cm long.
Growing on branches explains the care below. The roots want air as much as water, so the mix is chunky and dries between waterings, and the stems put out roots along their length, NC State says, to grip what they climb. The plant care guide has every other species on the site.
Types of hoya, from carnosa to kerrii
Care is close across the common hoyas; what differs is leaf, habit and how readily they flower. Iowa State says Hoya australis often flowers sooner indoors than other species, while the sweetheart hoya, H. kerrii, is less vigorous and more particular about light and humidity. RHS recommends H. lanceolata subsp. bella and H. linearis for a hanging planter.
One trap: Iowa State says H. kerrii is often sold as a single heart-shaped leaf with no node. That leaf roots but never grows a vine, and stays a single leaf with no new growth. Buy one with a piece of stem.
| Variety | What it looks like | Habit | Suits a pocket? |
|---|
| Hoya carnosa | Thick, waxy green leaves; white to pink star flowers | Climbs or trails | Yes |
| Hoya carnosa ‘Krimson Queen’ (‘Tricolor’) | Green centre, creamy white to pink margins | Climbs or trails | Yes |
| Hoya carnosa ‘Krimson Princess’ | Pink and white variegation inside dark green margins | Climbs or trails | Yes |
| Hoya carnosa ‘Compacta’ (Hindu rope) | Tightly curled leaves close along the stem | Trailing, much slower | Yes |
| Hoya pubicalyx | Lance-shaped leaves flecked silver; deep pink flowers | Vigorous vine | Yes |
| Hoya australis | Round to oval bright green leaves | Vigorous vine | Yes |
| Hoya obovata | Round, thick leaves | Vine | Yes |
| Hoya lanceolata subsp. bella | Small fleshy leaves on downy stems | Compact, trailing | Yes, made for hanging |
| Hoya linearis | Narrow fleshy leaves on slender stems | Trailing | Yes, made for hanging |
| Hoya kerrii, single leaf | One heart-shaped leaf with no node | Does not grow | No, it never makes a vine |
Does a hoya like full sun?
No, bright light without hot sun. Iowa State describes the right spot as bright enough to cast a shadow or read a book by, often one of the brightest windows in the house, and says direct sun scorches or reddens the leaves. RHS keeps hoyas bright but out of hot summer sun, and Clemson puts them close to an east-, west- or south-facing window.
Too little light shows as thin growth and few flowers, Iowa State says, so this is not a plant for a dim corner; plants for a low light room covers the ones that are.
Keep it warm and out of draughts. RHS grows hoyas at 16 to 24°C and away from radiators and cold draughts, and Iowa State gives 18 to 27°C. NC State says it loves high humidity, RHS that it dislikes dry air while growing and stands the pot on damp gravel, while Iowa State says it adapts to average indoor humidity.
How often to water a hoya
Water thoroughly, then let the mix dry before the next watering, not on a set day. How dry is where the sources differ: NC State lets the soil dry out, Iowa State lets it dry almost completely, and Clemson lets it dry out completely and judges it by the weight of the pot. RHS keeps it moist but never waterlogged while it grows, and from October to February waits until it is fairly dry, but never completely.
Too wet is the bigger risk. RHS names root rot from wet, poorly drained compost and warns that damp compost in winter rots the roots. NC State says both too wet and too dry soil can make the leaves drop, and to use room-temperature water, since cold water can shock the plant. What yellow leaves are telling you sorts out the other causes of leaf drop.
Compost, feeding and repotting a hoya
Use a chunky, airy mix. Clemson uses equal parts potting soil, orchid bark and perlite, RHS equal parts orchid bark, peat-free multi-purpose compost and coarse perlite, and Iowa State a similar blend, because the roots need oxygen and should not sit in soggy mix.
Feed lightly. RHS feeds every couple of weeks in spring and summer with a balanced orchid feed, once a month in autumn and winter, and flushes the pot with plain water every few months; Iowa State feeds at half or quarter strength in spring and summer and not at all in winter. Keep it snug: Iowa State says hoyas flower better slightly pot-bound, and RHS repots only once the roots fill the pot, into one only a few centimetres larger.
How to get a hoya to flower
Light first. Iowa State calls bright light the primary driver of flowering, and RHS says failure to flower may be due to insufficient light. Then patience: NC State says most plants do not flower until they are two or three years old, and Iowa State adds a snug pot, light feeding in the growing season and a slight drop in night temperature.
Leave the flower stalks alone. NC State says the spur that carried flowers produces flowers again over several years, and RHS says new blooms often sprout from the stumps of old clusters, so never deadhead. Do not move a plant in bud either: RHS and Iowa State both say a change in light or watering can make it drop its buds. Indoor plants that flower again covers the other houseplants that rebloom.
The flowers come in clusters of up to 30 star-shaped blooms, NC State says, white to pink and waxy. Iowa State says they are fragrant, especially in the evening, and that some produce enough nectar to be messy; NC State says they may produce a sticky sap.
Do hoyas like to hang or climb?
Either. RHS gives a hoya a wire loop or a tripod of canes to climb, or a hanging container or high shelf to trail from. NC State describes carnosa as a climber and recommends it for hanging baskets.
RHS prunes lightly in late winter or early spring, cutting overcrowded or weak shoots just above a side shoot or leaf, and never the flower stalks. Hanging plants that last indoors covers where a trailing plant keeps its leaves.
Can a hoya go outside?
For the warm months, in shade. NC State lists it for patios with partial shade and brings it in once nights fall below 10°C. RHS sets the same 10°C winter minimum for carnosa, and Iowa State says hoyas do not tolerate temperatures below 13°C. Keep it out of direct sun, which Iowa State says scorches the leaves.
Is a hoya safe for cats and dogs?
Yes. The ASPCA lists Hoya carnosa, the sweetheart hoya and Hoya pubicalyx as non-toxic to cats and dogs, and NC State adds horses. The peperomia is on the same list, for a smaller pet-safe plant beside it.
RHS still wears gloves to prune it, because the milky sap can irritate skin. A chewed plant loses its leaves and, worse, its flower spurs, so a wall or a high shelf keeps both out of reach.
A hoya on the wall
Hung high, a hoya trails, and RHS and NC State both suggest a hanging container or a high shelf for it. On a wall the stems hang down over the board and the flower clusters open at eye level, where the evening scent is easy to catch. Living wall systems, compared covers the other ways to put plants on a wall.
A pocket stands proud of the wall with air on every side, so the substrate dries from more directions than a pot on a shelf does, which suits a plant that wants to dry between waterings. The Medium pocket holds 1.8 litres of substrate, about what a 15 cm pot takes, and Iowa State says hoyas flower better slightly pot-bound. Keep it off a wall in hot summer sun or above a radiator.
The board hangs by a slot near its top on one wall hook, so the wall side is one screw, one plug and one drilled hole. Treat the filled weight like a heavy framed picture: plasterboard takes an expanding plug, brick a standard one, and a tiled wall needs a tile bit before the masonry bit. The mounting guide goes through it step by step.
- Fill the pocket halfway with a chunky mix of compost, orchid bark and perlite.
- Ease the plant out of its pot, keeping the root ball whole.
- Set it slightly forward so the stems hang clear of the edge, then top up and firm gently.
- Water with room-temperature water until it drains, then let it dry.
Hoya problems and how to fix them
| What you see | Why | The fix |
|---|
| No flowers after several years | Too little light, a pot too big, or cut spurs | Move it to the brightest window, keep it snug, never cut the spurs. |
| Buds dropping before they open | A change in light or watering | Do not move the plant once buds form; water steadily. |
| Leaves dropping, blackening, stems dying back | Wet, poorly drained compost or a cold winter | Let it dry, repot into chunky mix and keep it above 10°C. |
| Scorched or reddened leaves | Direct sun | Move it back into bright, indirect light. |
| Sticky drops on the leaves or floor | Flower nectar, or sap-sucking pests | Nectar is harmless; if there are no flowers, check for mealybugs and scale. |
| White cotton in the leaf joints, or bumps on stems | Mealybugs or scale insects | Wipe them off and keep the plant apart from others. |
How to propagate a hoya
NC State, RHS and Iowa State all propagate hoyas from stem cuttings, and RHS also by layering. Iowa State says a leaf cutting roots but will not grow a vine without a node, so every cutting needs one. Mealybugs are the pest all three name first; how to get rid of mealybugs covers the white cotton in the leaf joints.
- Cut a length of last year’s stem with one or two nodes, in spring or early summer, as RHS does.
- Remove the lowest leaves so the nodes are bare.
- Stand the nodes in water, or in moist sphagnum or cuttings compost; RHS says roots form in two or three weeks in water.
- Once there are plenty of roots, pot it into a chunky, free-draining mix.
- To layer instead, peg a low stem onto the compost of a second pot and cut it free once it has rooted.
Is a hoya easy to care for?
Yes, if it gets enough light and is not overwatered. Clemson calls hoyas resilient, and names root rot from overwatering as the main threat.
Should I cut off dead hoya flowers?
No. Leave the flower stalk in place, because NC State and RHS both say new flowers grow from the same spur. Let the spent flowers fall on their own.
Why does my hoya smell at night?
The flowers are fragrant, especially in the evening, Iowa State says. Clemson names Hoya nummularioides as the most fragrant species.
Is a hoya a succulent?
Its leaves are. NC State says the name carnosa refers to the thick, succulent foliage, which is why it is left to dry between waterings.
How big do hoya flowers get?
Hoya carnosa’s individual flowers are under 2.5 cm across, in clusters of up to 30, NC State says. Clemson says Hoya imperialis has flowers up to 10 cm across.
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