Alocasia ‘Sedenii’

The hybrid background of Alocasia ‘Sedenii’

The cross behind ‘Sedenii’ brings together Alocasia cuprea and Alocasia longiloba ‘Lowii’. A. cuprea grows on rocky Bornean rainforest slopes. A. longiloba occupies humid Southeast Asian forest floors, ravines and pockets of soil among boulders.

Both parent species come from humid habitats with quick drainage.

Growing and caring for Alocasia ‘Sedenii’

• Light: Give ‘Sedenii’ bright, filtered light. Strong direct sun can damage its broad leaves.
• Humidity: Aim for approximately 65–80%.
• Watering: Keep the root ball lightly moist; water as the surface begins to feel less damp and allow the pot to drain fully.
• Temperature: Maintain 23–28°C.
• Substrate: Use bark, perlite or pumice and a moisture-retaining organic component.
• Feeding: Apply balanced fertiliser at moderate concentration during active growth.
• Repotting: Select a small, close-fitting pot. Repot when the roots occupy most of the available space.
• Propagation: Raise new plants from offsets or small corms. Keep developing roots warm, lightly moist and well aerated.
• Handling safety: Before repotting or unpotting, disturbing the root ball, cutting, pruning, division or propagation, wear gloves and keep Alocasia sap away from skin and eyes. After handling, wash hands and clean tools.

Recognising and resolving problems with Alocasia ‘Sedenii’

• Separate new blisters become corky: Distinct translucent-to-corky marks support oedema; stable colour or relief alone does not. Empty standing water, clear drainage, reduce prolonged saturation in cool or dim conditions and improve gentle airflow. Existing corking remains. A flat, soft or expanding lesion needs isolation, dry foliage and splash control; if one severely affected leaf must be removed, wear gloves and keep sap away from skin and eyes before cutting it with a disinfected tool, discard it and disinfect the tool again, then wash hands and clean tools. Recurrence, rapid spread or petiole or crown entry needs professional diagnosis.
• Fine stippling, progressive bronzing or webbing appears: Check beneath leaves and around junctions for mites or eggs. Isolate, rinse both surfaces and reduce dust. If live mites or fresh damage remain, use a product labelled for spider mites and indoor ornamentals, test a small area and repeat only at the label interval.
• Petioles or the crown suddenly lose firmness: Check whether the root ball is dry and light or wet and heavy. Water thoroughly and drain only when dry; when wet, stop watering and empty standing water. If decline persists, wear gloves and keep sap away from skin and eyes before unpotting; after handling, wash hands and clean tools. If the roots and crown are firm, do not cut; correct drainage, aeration, pot fit, light or temperature and monitor. Remove only directly confirmed dark, mushy, hollow, slimy or collapsing parts with disinfected tools, and use fresh airy medium in a clean draining pot fitted to the surviving roots. Seek professional diagnosis before cutting an unclear or soft crown.
• Margins become crisp: Check actual root moisture, mineral crust, feeding history, exposed heat, cold and persistent dampness. Water and drain only when dry; flush salts only with firm roots and free drainage. If poor drainage requires root-ball disturbance, wear gloves and keep sap away from skin and eyes before unpotting, use fresh airy medium in a clean draining pot sized to the surviving roots, then wash hands and clean tools. Pause feeding during stress and assess later growth.

Alocasia ‘Sedenii’: toxic if chewed

• Pets: This Alocasia is toxic to cats and dogs. Keep the plant and any cut pieces where pets cannot chew them.
• Children and handling: Keep it out of reach of children. Sap from damaged tissue can irritate skin and eyes, so wash your hands after pruning and avoid touching your face.
• Why it irritates: Alocasia tissue contains insoluble calcium oxalate crystals. Chewing or contact with sensitive tissue can cause immediate local irritation.
• Possible symptoms: Mouth exposure can cause burning pain, drooling, swelling, nausea or vomiting, and difficulty swallowing.
• After exposure: For a pet, contact a veterinarian. For a person, remove any plant material from the mouth and rinse with water; seek medical or poison-control advice if symptoms are significant. Breathing difficulty or rapidly increasing swelling needs urgent medical attention.

Who Sedenii honours

Sedenii honours nineteenth-century Veitch hybridizer John Seden.

The artificial hybrid Alocasia × sedenii Veitch was published in Gardeners’ Chronicle in 1869. The hybrid formula is Alocasia cuprea × Alocasia longiloba.