Alocasia infernalis 'Black Magic'

Alocasia infernalis 'Black Magic'

Alocasia infernalis 'Black Magic' is a small Bornean Alocasia with glossy, deep purple to purple-black leaves and a small upright growth. Mature foliage can appear almost black in soft light, then flash violet, green or metallic purple as the surface catches the light. The plant’s scale stays contained, with smooth, reflective foliage dark enough to give the whole base a dense shadowed look.

Alocasia infernalis P.C.Boyce was described from Sarawak, Malaysian Borneo, and is recorded from the Kapit Division. The species forms a small robust herb to around 55 cm tall, with slender petioles around 20 cm long and peltate ovate-triangular blades often around 15 × 10–12 cm, sometimes larger. Adult leaves are ascending, glossy and very deep purple on both surfaces.

Deep purple-black jewel foliage

Young plants can show metallic purple leaves with changing intensity, while mature plants develop darker, lustrous purple-black blades. The leaves are peltate, with the petiole attaching into the blade, and the smooth surface reflects light strongly. On mature leaves held at an angle, the blade shifts between violet and near-black.

Growth stays compact. The stem is slender, first upright and eventually able to lean slightly with the active shoot tip rising. Several leaves can sit together on a mature cultivated plant, giving a small but full base. The leaves are thinner than the heavy bullate Alocasia, so they show handling marks, low humidity and pest damage quickly.

• Leaf colour: glossy deep purple to purple-black, with metallic violet shifts in angled light.
• Leaf shape: peltate, ovate-triangular blades with smooth margins and an acute tip.
• Plant size: described as a small robust herb to around 55 cm tall.
• Growth habit: compact habit with slender petioles and ascending adult leaves.
• Indoor placement: warm cabinets, vitrines, shelves and small plant stands where humidity can stay steady.

Sarawak lowland forest conditions

Alocasia infernalis is native to Borneo, with records from Sarawak. The original collection locality is in the Kapit Division around Nanga Gaat, and the species grows in moist to ever-wet lowland forest. Habitat notes place it in valley bottoms on deeply leaf-litter-covered red sandstone-derived clay-loams in heavy shade at around 182–249 m elevation.

Indoors, Alocasia infernalis needs warm, humid, filtered-light cultivation. It is adapted to shaded forest conditions, and indoor plants still need enough brightness to maintain strong foliage and root activity. The root system should sit in a mix that holds light moisture while letting air return after each watering. Warmth and root aeration are especially important for a small, shade-adapted Alocasia.

Root warmth for Black Magic

• Light: Give a bright position away from harsh sun or gentle filtered light. Soft brightness keeps new growth steady and surface sheen, while hot direct sun can scorch the glossy leaves.
• Watering: Check below the surface before watering; a cool, heavy pot should wait.
• Substrate: Use a fine-to-medium airy mineral mix with bark, coco husk, perlite, pumice or similar mineral aeration and a moisture-holding base.
• Temperature: Keep the root zone warm enough that moisture clears before the base weakens.
• Humidity: Aim for around 70–85% where possible. Warm cabinet or vitrine conditions can help the leaves expand cleanly and keep edges from crisping.
• Feeding: Feed lightly when new leaves are forming with a diluted balanced fertiliser. Gentle nutrition matches the compact root system and helps limit salt build-up.
• Air movement: Use gentle air movement in enclosed setups so moisture dries from the base at a steady pace.
• Mineral substrates: Alocasia infernalis can adapt to inert mineral or semi-hydro substrates after a careful transition, with a warm, active root zone and balanced nutrients.

Container drying and enclosed displays

Alocasia infernalis 'Black Magic' grows well in small warm displays when humidity, airflow and pot drying stay balanced. A cabinet or vitrine can preserve the leaf finish, but the pot still needs to dry at a sensible pace. The plant should sit in a container close to the root mass, because oversized pots can keep the lower mix wet long after the surface looks ready.

In darker months, growth may slow or pause. A firm base and stable leaves are good signs during this period. Reduce watering frequency according to pot drying, keep the plant warm and avoid dividing or repotting during a quiet phase. Once active growth resumes, new leaves should open with stronger petioles and a clearer glossy finish.

Leaf finish under humidity stress

• Crisp edges: Check humidity, heat load and watering consistency. Thin dark leaves can mark quickly in dry air.
• Yellowing leaves: Inspect pot weight, lower mix moisture and root temperature. Wet cool substrate can cause rapid decline.
• Dull or dusty surface: Check for dust, hard-water marks or spider mites. Clean mature leaves gently with a soft damp cloth.
• Soft petioles: Review roots, temperature and recent watering. Petiole weakness often starts below the soil surface.
• Small new leaves: Recent transport, low root warmth, poor light or tired substrate can reduce leaf size for one growth cycle.
• Pest inspection: Sap-feeding pests are easy to miss on dark foliage. Inspect the glossy leaf backs and petiole bases while new growth is soft.

Older leaves and division

Remove fully yellowed leaves at the base with clean scissors once they have faded. Keep healthy dark leaves in place because the compact habit relies on each functioning blade. Avoid heavy rubbing while leaves are still soft; newly opened foliage can bruise before the surface has hardened.

Divide firm offsets or corms while roots and new leaves are active. Young pieces need warmth, high humidity and a modest container with an open substrate. Mature plants can produce paired inflorescences with a spathe and spadix; descriptions record a purple-marked spathe limb and bright orange to red berries. Indoors, the foliage stays glossy, compact and very dark.

Displaying very dark foliage

Alocasia infernalis 'Black Magic' contains insoluble calcium oxalate crystals. Place it safely away from chewing pets and young children. Wear gloves when cutting or dividing the plant if your skin is sensitive.

Infernalis and dark Bornean foliage

Alocasia infernalis P.C.Boyce was published in Gardens’ Bulletin Singapore in 2007 in the Araceae family. The epithet infernalis comes from Latin for infernal, chosen for the deep purple-black leaves of mature plants.