Araceae
Alocasia
Grown from a corm rather than a simple root ball, and the only aroids here that genuinely go dormant. Most of the reputation for being difficult comes from people treating a dormant corm as a dead plant.
Native to Tropical and subtropical Asia and eastern Australia
Species
No species published in this genus yet. Its photographs are in the gallery.
How Alocasia generally wants to be treated
Species pages start from this and record only where they differ.
- Light
- Bright indirect, and more of it than most people give them. They will not tolerate direct midday sun, but too little light produces weak petioles that cannot hold the leaves up.
- Water
- Evenly moist in growth, never waterlogged and never bone dry. They are quicker to collapse from either extreme than Monstera or Philodendron.
- Humidity
- 60% and up. Below 50% spider mites become a matter of when rather than if.
- Temperature
- 18-29 °C. Below about 15 °C they drop leaves and go dormant, which is normal rather than fatal.
- Substrate
- Airy but moisture-retentive — bark and perlite with enough coir or sphagnum that it does not dry out in a day.
- Fertilizer
- A balanced feed at half strength every third watering through spring and summer. Nothing at all once growth stops.
- Propagation
- Offsets and corms separated at repotting. Corms can be rooted in damp sphagnum in a closed container.
- Dormancy
- Real and expected. In lower light and cooler temperatures they drop leaves and rest as a corm. Keep the mix barely damp, stop feeding, and do not repot — most losses happen when a dormant plant is treated as a sick one.
- Common problems
- Sudden leaf loss in autumn is usually dormancy, not death — check the corm before discarding anything
- Spider mites are the defining pest of this genus; inspect leaf undersides weekly in dry air
- Drooping petioles that do not recover after watering usually mean rot at the corm
- Guttation — water beading at the leaf edge — is normal and not a symptom
These are the Alocasia defaults. The rules that hold across everything — what bright indirect actually measures, when to water, what humidity does and does not do — are on the general plant care page.