Colocasia Care Guide

Colocasia is the genus that gave the tropics its starch: C. esculenta, taro, has been cultivated for thousands of years and is still a staple crop across Asia and the Pacific. The ornamental side of the genus is a recent, collector-driven development, and the appeal is the leaf. Peltate blades attach to the petiole near the middle rather than the edge, so the leaf hangs like a shield and the stem meets it with a small dimple the trade calls the eye. Dark-leaved selections such as Bagaskara carry that form in near-black, and collectors buy them for the colour of a single leaf.

Growing Colocasia

• LightBright light to gentle sun; it needs more light than a houseplant usually getsColocasia wants more light than the shelf it is usually sold from suggests. Bright light with a couple of hours of gentle morning sun keeps the leaves dark and the stems short; deep shade stretches the petioles, fades the leaf colour and leaves the plant leaning for a window it will never reach.
• WaterKeep the soil permanently moist; it tolerates standing water at the baseThis is a plant that grows in wet ground, and it should be treated that way. Keep the soil permanently moist, and stand the pot in a saucer with water in it if the mix drains fast. Dry soil is the one mistake it does not forgive: the oldest leaves yellow and collapse within days.
• Humidity70% – 85% relative humidity once acclimatisedSeventy to eighty-five percent is where the big leaves size up properly, and it is a fair description of a wet tropical season. Indoors it accepts less, but the leaf edges crisp when the air falls below half. Grouping plants and a wide saucer of water do more than misting, which raises humidity for minutes.
• SubstrateRich, moisture-retentive soil with compost and peatRich, heavy and water-retentive: garden soil, compost and peat, with a little sand if it holds too much. Colocasia is a heavy feeder and a heavy drinker, so the mix should hold both water and nutrients. A free-draining aroid mix will keep the plant alive but the leaves will stay small.
• Temperature20 °C – 32 °CTwenty to thirty-two degrees, which is the range of a warm tropical lowland rather than a cool room. Below fifteen the plant stops growing and the leaves yellow; below ten the corm itself is at risk. It is the one aroid here that resents a cold windowsill through winter.
• PropagationCormel division while the plant is dormantLift the plant when it has died back, and the corm will be ringed with cormels the size of a thumb. Twist those off, let the cut surfaces dry for a day, and pot them in the same rich mix. Each cormel becomes a plant in one season, and one corm yields several.

Growth is fast and above ground for most of the year: a good corm pushes leaves in succession, each one larger than the last, and a plant can go from a thumb-sized cormel to a metre of leaf in a single warm season. That speed is what makes it forgiving — it recovers from bad treatment by pushing a new leaf rather than sulking for months. It is demanding in two ways only. It will not tolerate dry soil, and it will not tolerate cold. Give it wet feet, warmth and rich feeding, and it is one of the easiest aroids to grow well.

Bare-root export and transit

Export is straightforward because the plant carries its own reserve. The corms travel bare-root, washed free of substrate, dipped in anti-fungal and bactericide solution and packed with their root mass wrapped in sterile Chilean AAA sphagnum held damp. Each plant goes into an EPS-insulated box inside a corrugated carton, and that box holds an internal buffer of 18 °C – 24 °C against the cold of a freight hold. The nursery itself runs at 70% – 85% RH and 18 °C – 32 °C, which is close to the plant's own range, and the sealed climate box keeps condition for 7 – 10 days.

Questions buyers ask