Hoya callistophylla (Kalimantan form)

Origin of Hoya callistophylla (Kalimantan form)

Hoya callistophylla (Kalimantan form) comes from Kalimantan on Borneo.

Hoya callistophylla is native to Borneo. The individual selection history of this cultivated form is still uncertain.

Everyday care for Hoya callistophylla (Kalimantan form)

Use chunky, airy potting mix in a pot with drainage holes. Water once the pot is noticeably lighter and the deeper mix feels mostly dry. Soak it thoroughly and empty the saucer. The mix will take longer to become mostly dry when light, temperature or growth decreases, so check it before the next watering.

Give the stems a support in bright indirect light, protected from harsh sun. About 18–26°C is suitable, with a minimum above approximately 12°C. Aim for relative humidity above 50% and gentle airflow where possible; average room humidity is also tolerated.

Feed with balanced orchid fertiliser about every two weeks during new growth, following the label. Pause when growth stops. Repot one size larger only when roots outgrow the pot. If the mix alone has deteriorated, refresh it in a container that still fits the root ball. Check for fertiliser already in the new mix before feeding again.

For propagation, use a clean blade and gloves to take a stem section with at least one node. The sap can irritate skin. Remove the lower leaves and root that node in lightly moist propagation mix, keeping the remaining leaves above the mix. Provide warmth and indirect light; transfer to a small pot once rooted.

How to solve common problems with Hoya callistophylla (Kalimantan form)

• Several yellow leaves while the pot 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.
• Fine speckling (stippling) or webbing on the leaves: 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.
• Waxy insects beneath leaves or in leaf joints: Confirm mealybugs beneath the wax and isolate the plant. Remove visible insects with a damp swab or tweezers. Inspect sheltered leaf joints, stems, the pot and any support weekly, removing any mealybugs you find until none remain. If mealybugs persist, use a product approved for home use against mealybugs on indoor ornamental plants in your country. Follow the label for how much to use, where to apply it, when to repeat treatment and all safety precautions.

Hoya callistophylla (Kalimantan form) 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.

About the name Hoya callistophylla

Hoya honours the English gardener Thomas Hoy. Callistophylla combines Greek kallistos, meaning most beautiful, with phyllon, leaf, and refers to the species’ prominent leaf veins.

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

Ted Green first described Hoya callistophylla in 2000 in Fraterna, volume 13, issue 4, page 2.