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Plant care

Sulawesi Wax Plant (Sulawesi hoya) care

Hoya sulawesiana

Also called Sulawesi wax plant, Sulawesi hoya.

RHS H1bUSDA 11-12Pet-safeIndoor Typically 0.6–1.5 m indoors

Watering rhythm

10-14days

Every 10–14 days in the growing season; every 3–4 weeks in winter

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Light

Bright indirect light (just back from a sunny window)

Soil

Well-draining mix rich in organic matter

Humidity

60–75%

Temp

18–26°C

Pet safety

Pet-safe

Mature size

Typically 0.6–1.5 m indoors

Care at a glance

Light

Sulawesi Wax Plant is what florists mean by "bright spot, no direct sun" — close enough to a south or east window to feel the brightness, with a sheer curtain or a few feet of distance keeping the sun off the leaves. Bright filtered light best preserves leaf colour and structure; foliage develops attractive purple hues with more light but prolonged direct sun will scorch leaves. A phone lux-meter at the leaf surface should read 1,500-3,000 lux at noon.

Watering

Water sulawesi wax plant every 10–14 days in the growing season; every 3–4 weeks in winter. The actual day count varies with pot size, light, and season — the finger test (or lifting the pot to feel its weight) is more reliable than a fixed calendar. Empty any drainage saucer afterwards so the pot isn't sitting in water. Allow the soil to dry out almost completely before watering; never let the pot sit in excess water as this species is particularly susceptible to root rot.

Soil and pot

Sulawesi Wax Plant grows best in well-draining mix rich in organic matter. Use a blend of coco coir, perlite or vermiculite, and a small amount of orchid bark; the mix should drain freely while retaining just enough moisture to prevent the roots from completely desiccating. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Sulawesi Wax Plant sits happiest at around 60–75% humidity and 18–26°C (64–79°F). Coming from Indonesian lowland forest, this hoya thrives above 60% humidity; use a pebble tray or humidifier in heated indoor environments during winter. If you keep the room above 18–26°C year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed sulawesi wax plant sparingly. Feed monthly with a balanced liquid fertiliser at half strength during spring and summer; do not feed in autumn and winter when growth slows. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on sulawesi wax plant in the Growli community. Each is annotated with the most common cause so you know where to start.

  • Root rot from overwatering — The most common cause of failure with this species; mushy stem base and rapid leaf yellowing indicate the roots are rotting. Remove from pot, trim dead roots, allow to dry out, and repot in fresh fast-draining mix — water much less frequently going forward.
  • Slow growth and reluctance to flower — H. sulawesiana is uncommon in cultivation and can be a slow establisher; insufficient light is the most frequent reason for stunted growth and no blooms. Move to the brightest indirect spot available and ensure temperatures stay above 18°C year-round.

Propagation

Root 10–15 cm stem-tip cuttings in moist perlite or sphagnum moss inside a closed propagator or plastic bag at 24–28°C; rooting typically takes 4–8 weeks. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Sulawesi Wax Plant is pet-safe. The Hoya genus is listed as non-toxic to cats and dogs by the ASPCA. No toxic compounds are documented for H. sulawesiana; mild digestive upset is possible if pets ingest large amounts of plant material. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Sulawesi Wax Plant care — frequently asked questions

What is the common name for Hoya sulawesiana?

Hoya sulawesiana is most commonly called Sulawesi Wax Plant, but it is also known as Sulawesi wax plant, Sulawesi hoya. The names refer to the same species, so care instructions for Sulawesi Wax Plant apply identically to anything sold as Sulawesi hoya.

How much light does sulawesi wax plant need?

Sulawesi Wax Plant grows best in bright indirect light (just back from a sunny window). Bright filtered light best preserves leaf colour and structure; foliage develops attractive purple hues with more light but prolonged direct sun will scorch leaves.

How often should I water sulawesi wax plant?

Water sulawesi wax plant every 10–14 days in the growing season; every 3–4 weeks in winter. Allow the soil to dry out almost completely before watering; never let the pot sit in excess water as this species is particularly susceptible to root rot. The finger-test (or lifting the pot to feel its weight) beats a fixed weekly calendar because pot size, light, and season all change how fast the soil dries.

Is sulawesi wax plant toxic to cats and dogs?

Sulawesi Wax Plant is pet-safe. The Hoya genus is listed as non-toxic to cats and dogs by the ASPCA. No toxic compounds are documented for H. sulawesiana; mild digestive upset is possible if pets ingest large amounts of plant material.

What USDA hardiness zone does sulawesi wax plant grow in?

Sulawesi Wax Plant is rated for USDA zone 11-12 (indoor in most climates) and RHS hardiness H1b. Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Sulawesi Wax Plant deep-dive guides

Every aspect of sulawesi wax plant care, each with its own calibrated guide:

Featured in these plant shortlists

Sulawesi Wax Plant qualifies for 11 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

Related guides

Sulawesi Wax Plant is also commonly called Sulawesi wax plant or Sulawesi hoya.