The Alocasia “Jewel” plant, native to Asia, and is also called an Alocasia Nebula. Alocasia plants have large, glossy, heart-shaped leaves with wavy edges. If you are searching for a dramatic, very different looking plant that can be as small as 6″ or as tall as a tree, an alocasia plant is a great choice. Alocasia plants are considered poisonous and should be kept away from pets and children. Read more about common houseplants that are poisonous in my book Don’t Feed me to Your Cat! A Guide to Poisonous Houseplants. These plants do require extra care and attention in order to stay looking good. Proper watering and high humidity help an Alocasia plant grow faster and not drop leaves.
An alocasia plant requires very bright indirect light. Direct sun burns the leaves.
Always allow the top 2″- 3″ of the soil to dry out before watering. Keep the soil evenly moist. Over- watering, wet leaves, and soggy soil makes an alocasia plant susceptible to a variety of serious fungal infections. Check the soil frequently until you are sure of the plant’s watering needs. Water less during the winter when it is dormant.
Fertilize every two weeks from late March through September with a balanced houseplant food diluted to 1/2 the recommended strength. Never fertilize an alocasia during the winter. Too much fertilizer causes salts to build up in the soil and burn the leaves.
Alocasia plants prefer warm temperatures between 60°-80°F (15.6°-26.7°C). Alocasia plants becomes dormant with prolonged exposure to temperatures below 60°F (15.6°C), and may drop all of their leaves. Be sure to keep an alocasia away from air conditioners and cold drafts. During warm summer months an alocasia plant can produce a new leaf every week and each new leaf may be twice the size of the previous leaf.
Alocasia plants grow best in high humidity. To increase the humidity around a houseplant, place the plant on a tray filled with pebbles and water. Be sure the plant is sitting on the pebbles and not in the water. You can also increase the humidity by placing a small humidifier near the plant or grouping plants together.
An alocasia macrorrhiza produces a cream colored spathe-like flower (really a modified leaf).
Spraying an alocasia with warm soapy water every few weeks helps prevent mealy bugs, scale, aphids, and spider mite problems. It also keeps the large leaves of the plant dust-free. If an alocasia plant does become infested with houseplant pests, spray with an ultra fine commercial insecticidal oil. This kills both the pests and their eggs.
When over- watered or when the leaves get wet, Aloasia plants may develop a variety of diseases such as Crown, Stem, and Root Rot, Leaf Spot, and Xanthamonas. These diseases usually appear as dark brown or black spots on the leaves surrounded by a yellowish rim. The best way to prevent plant diseases is to avoid over-watering, keep the leaves dry, and provide good air circulation around the plant. Once an alocasia is infected, quickly remove the damaged leaves and any leaves that have fallen off, isolate the plant from your other plants, and treat with a commercial fungicide.
Use an organic well-aerated loose plant soil that contains a good amount of peat moss. If the soil seems a little heavy, add some builder’s sand or perlite.
Alocasia plants prefer to be root-bound in small pots. Do not increase the size of the container until the roots have filled the existing pot and always move to the next size pot only.
Quickly remove any yellow leaves or those that develop brown or black spots as that may be a sign of a fungal disease.
Alocasia plants are propagated by plant division. You can read more about propagation techniques in the Glossary.
These plants become dormant during the late fall and early winter. Don’t be concerned no new leaves develop during this time.
Poisonous Plant Info
Alocasia plants are very poisonous houseplants with a #4 toxicity level.