There are many words you might use to describe the Alocasia genus: Stunning, architectural, and jewel-like are appropriate. These are very tropical collector’s plants that have a passionate following. In the right conditions, they can grow very fast, but they are also sensitive plants. Alocasia grows well in big pots; they can thrive in the summertime and then be brought indoors in the winter. The plant works equally well as a dramatic focal point in a mixed pot or as a background to more colorful varieties of flowers. Some species are considered invasive, especially along the Gulf Coast in the U.S. Check with your local municipality if you have concerns prior to planting this species outdoors. If you have children or pets, you may want to avoid these plants as the leaves are toxic to humans and animals.
- Botanical Name: Alocasia sanderiana
- Common Name: Alocasia, Elephant Ears, African Mask
- Plant Type: Tropical plant
- Mature Size: Range is size based on variety from 2 feet tall and 2 feet wide to 15 feet tall and 8 feet wide
- Sun Exposure: Bright indirect light
- Soil Type: Loose, well-draining potting mix or crumbly loam
- Soil pH: 5.5 to 6.5
- Bloom Time: Spring and Summer growth
- Flower Color: Light butter yellow
- Hardiness Zones: 10 and 11 for outdoor plants
- Native Areas: Asia
How to Grow Alocasia Plants
Even with a shorter growing season in northern climates, these plants can have rapid growth. In the warm summer months of the growing season, alocasia can produce a new leaf every week. Each new leaf may be twice the size of the previous week. The leaf shapes can vary from slim arrowheads to wide heart-shaped leaves. They have colorful veins and a variety of textures from thick, waxy, slick, and glossy.
Once the plant is in its dormant period (in the late fall and winter), it will begin resting. The rapid leaf growth will be quite diminshed and the plant will likely remain as-is throughout the season. Continue to care for it, and the rapid growth will return the following growing season.
Needs vary from shade to full sunlight, depending on the variety. Ask the grower if the plant is sun-trained. Leaf color tends to be better among plants that grow best with more light.
Plant in loose, well-drained potting mix or a crumbly loamy soil. Try to let the top few inches of soil become nearly dry before watering. This will help keep it evenly moist. Soggy soil makes the plant susceptible to many fungal infections.
Keep Alocasia plants moist all year; they grow best in very high humidity. They are water-loving plants. There is a fine line with these plants. You want to keep the soil moist, but not soggy. They require less water during the winter months because the plant is dormant.
Temperature and Humidity
Alocasias will start to suffer below 60 degrees Fahrenheit. Some varieties will die back during colder weather and resprout from the rhizome. They thrive in very humid environments. To raise the humidity around your plant, place it on a tray filled with pebbles and then add water until it rises to just below the bottom of the pot. Keep them away from cold drafts from windows, doors, and air conditioning.
Alocasias can be heavy feeders, especially large specimens. Feed with liquid fertilizer during the growing season or frequent, small applications of granule fertilizer.
Potting and Repotting
Repot Alocasia varieties annually into larger pots with fresh, free-draining potting soil. Also, it's best to divide the rhizome annually to keep the plant a manageable size and increase your collection.
Propagating Alocasia Plants
Most Alocasia plants can be propagated by clump or rhizome division. Cut off a piece of the underground rhizome and pot it up separately, then keep it warm and moist until new growth begins.
Varieties of Alocasia Plants
There are about 70 species of Alocasia, as well as dozens of hybrids. Alocasia plants are primarily hybridized because of the appeal of their leaf form, color, and sizes. Some include:
- The jewel-like Amazon lily (Alocasia Amazonica), which can grow to 2 feet tall and wide
- The truly enormous Alocasia macrorrhizos, which can grow up to 15 feet tall and 8 feet wide
Additionally, the plant has been extensively hybridized. Most Alocasia species will do all right in shade, but they often appreciate slightly brighter filtered sunlight. The bigger ones can be trained to handle full tropical sun. Keep all species warm, moist, and humid. Trim away falling leaves. Like all aroids, Alocasias flower with a typical spathe and spadix, but the flower is usually unremarkable and can even be slightly vulgar.
Common Problems of Alocasia Plants
While quite striking, these plants can be quite sensitive, especially to over-watering. A variety of diseases including crown, stem, and root rot, Leaf Spot, and Xanthamonas are particularly common with alocasia plants. Signs of diseases are typically black or dark brown spots on the leaves and a yellowish rim around the spots. Diseases can be prevented by avoiding over-watering, keeping the leaves dry, and providing proper air circulation around and near the plant.
Common pests of the Alocasia plants are Mealy Bugs, scale, Aphids, and spider mites. Every few weeks, you can spray the plant with warm soapy water to prevent these pests. This will help keep the plant dust-free. If an infestation does occur, use an ultra-fine insecticide oil or Neem Oil. These products will kill the pests and their eggs.
Toxicity of Alocasia Plants
The Alocasia is a very poisonous plant; the leaves contains insoluble oxalate crystals. If a human or pet chews or bites into the leaves, they will release the crystals. It can cause swelling and irritation of the mouth and GI tract. Very rarely, there will be extreme swelling of the upper airway, making it difficult to breathe. Keep the plant away from children and pets and call poison control, your doctor, or vet if a person or animal ingests the plant leaves.