Giant Taro

How to care for Giant Taro

Light

Alocasia macrorrhizos thrives in bright, indirect light that mimics the dappled canopy conditions of its native habitat. A position near a large east- or west-facing window is ideal; direct summer sun, particularly through south-facing glass, will scorch the leaves. It can tolerate lower light levels for short periods but will slow its growth considerably and become prone to overwatering issues if kept in deep shade for extended spells.

Watering

Water thoroughly when the top 2 to 3 cm of compost have dried out, allowing excess to drain freely from the pot. During the active growing season from spring through summer this may mean watering every five to seven days, but always check the compost rather than following a rigid schedule. Reduce watering significantly in autumn and winter when the plant enters a period of rest, as sitting in wet compost at lower temperatures is the most common cause of root rot. Use room-temperature water and avoid leaving the plant standing in a saucer of water.

Soil and potting

A well-draining yet moisture-retentive mix is essential. A reliable blend combines one part peat-free potting compost, one part perlite or pumice, and one part coarse bark chips. This replicates the loose, humus-rich forest floor soils the plant favours, provides adequate aeration around the roots, and reduces the risk of waterlogging. A slightly acidic to neutral pH of 5.5 to 7.0 is appropriate.

Feeding

Feed every two weeks throughout spring and summer with a balanced liquid fertiliser diluted to the manufacturer's recommended strength. A fertiliser with an NPK ratio of roughly 20-20-20 or one slightly higher in nitrogen suits the plant's need to support rapid, leafy growth. Cease feeding entirely from October through February when the plant is resting, as unused nutrients can accumulate as salts in the compost and damage roots.

Humidity and temperature

This species demands high humidity, ideally above 60%, and will develop brown, crispy leaf margins if kept in dry air. Group it with other plants, place the pot on a tray of damp pebbles, or use a cool-mist humidifier nearby; misting the foliage directly is less effective and can encourage fungal spots. Keep temperatures between 18 and 30 C and protect the plant from draughts, cold windowpanes in winter, and temperatures below 15 C, at which point growth ceases and corm rot becomes a serious risk.

Repotting

Repot every one to two years in spring when roots are visibly emerging from the drainage holes or circling the base of the rootball. Choose a pot only one or two sizes larger than the current one, as an excessively large container retains too much moisture. Terracotta pots aid aeration and help prevent overwatering. At repotting, inspect the rhizome for any soft or discoloured rot and trim affected areas cleanly with a sterile blade, dusting cuts with powdered cinnamon or activated charcoal.

Pruning

Pruning is largely limited to the removal of old, yellowing, or damaged leaves. Cut the petiole cleanly at its base using sharp, sterile scissors or secateurs. Wear gloves during this task, as the sap contains calcium oxalate crystals that irritate skin and mucous membranes. Do not remove healthy leaves unnecessarily, as each leaf contributes to the plant's photosynthetic capacity; the plant naturally sheds older lower leaves as it matures.

Is Giant Taro toxic?

Common problems

How to propagate

Rhizome division

When repotting in spring, carefully separate offsets or suckers that have developed their own roots from the main rhizome using a clean, sharp blade. Pot each division into a small container of moist, well-draining compost and keep warm and humid until new growth is established.

Stem cuttings from the corm

Sections of the thick stem or corm, each containing at least one growth node, can be cut and allowed to callous for several hours before being placed in moist perlite or sphagnum moss. Maintain warmth of around 24 C and high humidity; roots and shoots typically emerge within four to eight weeks.

Seed

Seeds can be germinated at temperatures above 22 C in moist, well-aerated seed compost, though this method is slow, rarely practical for indoor growers, and requires access to fresh seed as viability declines rapidly.

Where Giant Taro comes from

Native to Bismarck Archipelago, Borneo, Maluku, New Guinea, Philippines, Queensland, Solomon Is., Sulawesi. Now naturalised or cultivated in 62 other regions worldwide.

Story and origins

The genus name Alocasia is thought to derive from the Greek prefix 'a', meaning without or distinct from, combined with Colocasia, the related genus of taro, indicating a plant closely allied to but distinct from Colocasia. The species epithet macrorrhizos comes from the Greek 'makros' meaning large and 'rhiza' meaning root, referring to the plant's substantial, fleshy rhizome or corm. The name was formalised by the German botanist Heinrich Wilhelm Schott in the nineteenth century as he worked to classify the large and complex Araceae family.

Alocasia macrorrhizos has a long history of human use across South and Southeast Asia and the Pacific. It was among the staple crops transported by Austronesian-speaking peoples during their migrations across the Indo-Pacific thousands of years ago, and it features in the traditional food systems and cultural practices of communities from India to the Solomon Islands. European botanists documented the species during the colonial era, with early descriptions appearing in the works of Georg Rumphius in the seventeenth century. In the nineteenth century it became a coveted foliage plant in European conservatories and stove houses, where its dramatic size made it a popular specimen during the Victorian enthusiasm for tropical exotica. Today it enjoys renewed popularity as a houseplant due to the widespread resurgence of interest in large-leaved tropical aroids.

Varieties to know

Alocasia macrorrhizos 'Variegata'

An uncommonly available cultivar with irregular cream, white, or pale yellow variegation on the large leaves; slower growing than the species and requires brighter indirect light to maintain colouration.

Alocasia macrorrhizos 'Lutea'

Distinguished by yellow-green petioles and midribs, giving the foliage a striking two-tone appearance.

Alocasia macrorrhizos 'Borneo Giant'

A particularly large-growing selection reputedly capable of producing leaves of exceptional size; mainly of interest to collectors with space for a specimen plant.

Fun facts

• In its native tropical habitat Alocasia macrorrhizos can grow leaves exceeding 1.8 metres in length and the whole plant may reach over 5 metres in height.
• The species is capable of a phenomenon called guttation, in which droplets of water are exuded from specialised pores at leaf tips and margins, sometimes mistaken by owners for condensation or a sign of overwatering.
• The large rhizome, known locally as 'biga' or 'ape', has been used as a famine food across Pacific island cultures for centuries, requiring prolonged cooking or fermentation to remove the toxic calcium oxalate crystals.
• Alocasia macrorrhizos is naturalised across much of the Pacific, including Hawaii, Fiji, and parts of Australia, having been introduced by Polynesian voyagers who transported edible root crops on ocean journeys.
• The plant produces a spathe and spadix inflorescence typical of the Araceae family, though it rarely flowers indoors; pollination in the wild is carried out by specific insects attracted to heat and scent generated by the spadix.

Giant Taro FAQ