Alocasia nebula ‘Imperialis’

Origin and horticultural identity of Alocasia nebula ‘Imperialis’

Alocasia nebula ‘Imperialis’ is a cultivated horticultural form associated with Alocasia nebula, a Bornean species native to Sarawak. Its precise wild locality remains uncertain; it has been associated with low-elevation rainforest over limestone near Semenggoh, Kuching, but its occurrence in the wild has not been confirmed.

This plant has also circulated under the older horticultural name Alocasia guttata var. imperialis sensu hort.

Care for Alocasia nebula ‘Imperialis’

• Feeding: While Alocasia nebula ‘Imperialis’ is pushing new foliage, use a complete fertiliser at a restrained rate; reduce feeding when leaf production slows.
• Humidity: Aim for 60–80% humidity with gentle airflow, especially while a new leaf is opening.
• Watering: Wait until the mix has begun to lose some moisture, then water until excess runs from the drainage holes. Let the pot drain, then empty any water left in the saucer or cover pot. Keep the roots from drying out completely.
• Potting mix: Use a very loose, rich mix that holds some moisture without becoming dense or waterlogged. If you include dolomite, use only a small amount of coarse crushed dolomite and avoid fine powder.
• Light: Keep it in shade to soft, filtered light. Strong sun can wash out or scorch the leaves.
• Temperature: ‘Imperialis’ grows steadily at about 18–29 °C. Use a warmer location when prolonged temperatures threaten to fall below 15 °C.
• Repotting: Move to a pot only slightly larger once the roots are filling the current pot.
• Propagation: Mature plants can produce small corms on thin runners. Some can stay dormant for a long time; keep a firm corm while it remains sound and wait for it to sprout.

When Alocasia nebula ‘Imperialis’ has problems

• The plant suddenly collapses after a cool period while the potting mix is still wet: Move it to a reliably warm place and do not water again while the potting mix is still very wet. Examine the roots and base, remove only material that is clearly rotten and replace the old substrate with a fresh, airy mix.
• Leaves develop washed-out patches after a sudden increase in light: Reduce the exposure and return the plant to shade or bright filtered light. The faded areas will not recover, but later leaves should open without further bleaching or scorch.
• Growth stops even though healthy roots are tightly packed through the pot: Give the root system a little more room. Move the plant only one pot size up and use an airy mix, rather than trying to restart growth with additional fertiliser.

Alocasia nebula ‘Imperialis’: 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.

What nebula and Imperialis mean

Nebula is Latin for “mist” or “cloud”, matching the clouded leaf colouring. Imperialis means “imperial”. Alistair Hay described Alocasia nebula in 2000 in Curtis’s Botanical Magazine, volume 17, page 16. ‘Imperialis’ derives from the historical name Alocasia guttata var. imperialis. In current horticultural use, ‘Imperialis’ functions as a historical trade label associated with Alocasia nebula.