How to grow alocasias

Why grow alocasias?

Alocasias are spectacular plants, ideal for creating a jungle look in your home. They usually have large, glossy, shield-shaped or pointed leaves with prominent veins. Alocasias originate in tropical forests, where they evolved extra-large foliage to catch the maximum amount of sunlight coming through the tree canopy overhead.

They like warm, humid conditions, in bright but not direct light. In summer, alocasias can be very fast growing, often producing leaves on a weekly basis. In winter, they need a period of dormancy, in cooler, drier conditions.

Alocasias are often known as elephant’s ear, due to their large leaves. They’re closely related to taro (Colocasia esculenta), a widely grown root crop in Africa and South-East Asia. Despite this, alocasias contain toxic compounds, so should not be eaten, and it’s best to wear gloves when handling them. Alocasias are in the arum family (Araceae), along with other popular houseplants such as the peace lily (Spathiophyllum) and Swiss cheese plant (Monstera deliciosa), and like similar growing conditions. See our guide to amazing arums.

Choosing alocasias

There’s a wide range of alocasias to choose from, with leaves of different shapes, sizes and colours. Some can grow very large, such as Alocasia macrorrhizos and A. odora, which can reach 1.5m (5ft) tall, creating a fabulous jungle effect, while others are more compact, ideal for a small bathroom or other similarly warm, humid spot.

Popular choices include:

• Alocasia x amazonica ‘Polly’ – one of the most widely available, with striking dark-green, silver-veined leaves 

• A. ‘Stingray’ – has leaves shaped like its sea-dwelling namesake

• A. ‘Sarian’ –  with upright, boldly veined, arrow-shaped foliage 

• ​A. lauterbachiana – has long, spear-shaped, wavy-edged leaves

A. amazonica has an RHS Award of Garden Merit, showing it performed well in growing trials, so makes a reliable choice.

Buying alocasias

Alocasias are usually available in garden centres and other houseplant retailers. For the widest choice, try online houseplant specialists.

When buying in person, choose healthy-looking plants with unblemished leaves and no signs of wilting or insect damage. As these are tropical plants, take care to keep them warm when transporting them, as low temperatures can damage or even kill them.

Alocasia can usually be left in their original pot for a year or so, but should then be repotted every couple of years, especially the faster-growing species. Check for overcrowded roots and repot in spring if necessary.

When repotting, choose a peat-free houseplant compost, or a peat-free multi-purpose compost and add perlite to improve the drainage – about three parts compost and one part perlite.

Choose a pot that’s only about 10cm (4in) in diameter larger each time, to avoid overpotting problems. Position the plant in the new pot so the top of the rootball is just below the surface of the compost. Larger alocasias are best planted in a heavy terracotta pot, to give them more stability.

It’s best to wear gloves when handling alocasias, as the sap can be an irritant.

See our guides on repotting houseplants:

Location

Alocasias grow best in bright but indirect light. Strong sunlight can scorch the foliage. While they can survive in lower light, their growth will be much slower.

Temperature

These tropical plants should be kept warm, above 16°C (60°F) throughout the growing season, from spring to autumn. Also keep them out of cold draughts.

In winter, give them cooler and drier conditions, but still above 10°C (50°F), to allow them to go dormant. They may lose some of their foliage during this time, but this is nothing to worry about. They’ll produce plenty of fresh leaves once they come back into growth in spring.

Watering

Water regularly from April to October, once the top 5cm (2in) of compost has become dry. Turn the plant round slightly at each watering to prevent it leaning towards the light and becoming lopsided and unstable.

If the compost begins to dry out very fast after watering, it’s usually a sign the plant is pot-bound and needs to be moved into a larger container – see Planting, above.

During winter, when the plant goes dormant, reduce watering to a minimum. Overwatering, especially while dormant, can cause the roots to rot.

Humidity

Alocasias like medium to high humidity through the growing season, but the air in our homes is often very dry. Try some of the following to keep your alocasia happy:

• stand the pot in a tray of gravel or clay granules, then add water to just below the surface of the gravel, and top up regularly as it evaporates 

• position the plant in a bathroom 

• mist the leaves

• group several plants together 

• use a humidifier

Feeding

To fuel the production of large leaves, feed with a general liquid fertiliser during the growing season, from April to October.

If you give alocasias the warmth, humidity, water and nutrients they need through the growing season, followed by a cooler, drier period over winter, they are usually vigorous, robust plants. Try to avoid the following:

• Low humidity – this can cause browning on the leaf edges and may attract red spider mites, which thrive in a dry atmosphere

• Watering too much in winter – or overwatering in general – can lead to root rot

• Cold draughts, particularly in winter, can be damaging

• Low temperatures – keep alocasias above 10°C (50°F) at all times, and during the growing season they need at least 16°C (60°F)