Hoya buntokensis

Background and history of Hoya buntokensis

Hoya buntokensis comes from near Buntok in Central Kalimantan, Borneo. One plant was found about 5 m up a small tree in lowland heath forest, above a stream and wetland at 100–300 m elevation. Sri Rahayu and Michele Rodda described the species in 2021.

How to keep Hoya buntokensis growing well

Choose bright indirect light for Hoya buntokensis, shielding it from hot direct sun. If you move it to a brighter position, increase light exposure gradually. Leaves may develop reddish colour in brighter light. Aim for about 16–24°C and 40–60% relative humidity during growth, with ventilation around the foliage. Support climbing stems or let them trail, and retain living flower stalks for repeat flowering.

Use an airy mix that lets excess water drain quickly. Lift the pot to check its weight as the mix dries. Once it feels noticeably lighter, water the whole root ball and drain fully. When growth slows, allow the mix to become fairly dry between waterings, without drying it completely.

Use balanced orchid fertiliser about every two weeks while new growth develops, following the label’s dose and frequency. Pause when growth stops. When roots fill the pot, move the plant into a container only a few centimetres wider.

Stem cuttings need at least one node. Wear gloves because the sap can irritate skin, and use a clean blade. Remove the lowest leaves and root that node in lightly moist propagation mix, keeping the remaining leaves above the mix. Provide warmth and indirect light; once roots form, move the cutting to a small pot of freely draining mix.

Common problems with Hoya buntokensis

• Dark spots spreading on damp leaves: Persistent wet foliage and poor airflow can favour leaf-spot problems, although appearance alone cannot identify the cause. Let the leaves dry and allow gentle airflow around the plant. When watering is due, apply water directly to the mix, keeping the leaves dry. If spots continue to spread, isolate the plant and remove badly affected leaves with a clean tool; seek a diagnosis before using a pesticide.
• Fine mottling with webbing: Inspect damaged leaf undersides with magnification; tapping a leaf over white paper can help locate mites. Confirm spider mites before treatment. Isolate the plant, gently rinse both leaf surfaces and let water drain. Recheck every few days and repeat rinsing while live mites remain. If spider mites persist, choose a product labelled for them on indoor ornamental plants. Test a small area first where the label allows, then follow its directions for the dose, repeat treatments and safety precautions.
• Wilting while the potting mix remains wet: Persistent wetness can damage roots. Drain trapped water and inspect roots if decline continues. If you find a small amount of root rot, use a clean, disinfected tool to cut the soft roots back to firm, healthy tissue. Throw away the rotten roots and old mix. Repot in fresh, airy mix, using a clean pot just large enough for the roots that remain. The pot must have drainage holes. If decay is widespread, save only healthy stem cuttings. Discard the plant if no healthy stems remain, and disinfect your tools afterwards.

Hoya buntokensis is non-toxic to people and pets

• This plant is non-toxic to people, cats and dogs.
• Chewing a large amount can still cause an upset stomach.
• If a large amount is eaten and symptoms continue, contact a veterinarian or medical professional.

Hoya buntokensis: where the name comes from

Hoya honours the English gardener Thomas Hoy. The species epithet buntokensis refers to Buntok in Central Kalimantan.

Robert Brown established the genus Hoya in 1810 in Prodromus Florae Novae Hollandiae, page 459.

Sri Rahayu and Michele Rodda first described Hoya buntokensis in 2021 in Blumea, volume 66, page 237.