Hoya glabra ‘Black Margin’

Origin of Hoya glabra ‘Black Margin’

Hoya glabra ‘Black Margin’ is a cultivated form of Hoya glabra. The species occurs naturally from Sumatra to northern and northwestern Borneo; this form's selection history is still uncertain.

A simple care guide for Hoya glabra ‘Black Margin’

Give the climbing stems a trellis and space for airflow around the leaves. Choose bright filtered light, with 60–80% relative humidity. Protect the plant from hot direct sun and cold draughts. Keep conditions at roughly 16–24 °C, shielding the plant from sustained temperatures below 10 °C.

Water a freely draining, airy mix when the pot feels lighter and the deeper mix is only lightly moist. Soak the roots and drain fully. When growth slows, wait until the mix is fairly dry before watering again, without letting the whole root ball dry out.

Use all-purpose fertiliser at 25–50% strength during new growth. Pause fertiliser until active growth resumes. Move into the next size only once roots fill the current pot.

Root a one- or two-node cutting in lightly moist sphagnum, loosely packed in a pot with drainage holes. Take cuttings with a clean blade. Remove lower leaves and keep the rest above the moss. Provide warmth, indirect light and humid air; hold any cover off the foliage and ventilate it. Pot into airy mix once rooted.

Understanding common problems with Hoya glabra ‘Black Margin’

• New dry, bleached patches on exposed leaves: The leaves naturally have dark margins and should feel firm. Hot sun or a sudden increase in light can scorch leaves, leaving new dry or bleached patches. Move the plant into bright, filtered light. If you later move it to a brighter position, introduce the stronger light gradually. Existing dry patches will not recover; retain healthy foliage.
• Large leaves soften or shrink in a dry pot: Check whether the mix around the roots is dry. If the root ball is dry, water thoroughly and drain. If the leaves still wilt after watering, inspect the roots. Avoid repeated watering while the roots are still wet.
• Soft, yellowing growth while the mix stays 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.
• Cottony insects at the leaf-stalk junctions: 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 glabra ‘Black Margin’ 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.

What does the name Hoya glabra mean?

Hoya honours the English gardener Thomas Hoy. Glabra means smooth or hairless.

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

Friedrich Richard Rudolf Schlechter first described Hoya glabra in 1908 in Beiblatt zu den Botanischen Jahrbüchern für Systematik, volume 92, page 14.