Repotting guide

When & how to repot Colocasia 'Illustris' (Imperial Taro) (Colocasia esculenta 'Illustris')

Also called Imperial Taro, Imperial Elephant Ear, Black Elephant Ear, Illustris Elephant Ear.

More about colocasia 'illustris' (imperial taro)

About Colocasia 'Illustris' (Imperial Taro)

Colocasia esculenta 'Illustris' · also called Imperial Taro, Imperial Elephant Ear · tropical

Colocasia 'Illustris' is a tuberous tropical grown for huge heart-shaped, blackish-purple leaves veined in bright green. It wants warmth, bright light and constantly moist, rich soil, plus regular feeding. It is toxic: the ASPCA lists Colocasia esculenta as poisonous to cats, dogs and horses, so keep it well away from pets.

Mature size: Typically 0.9-1.5 m (3-5 ft) tall and 0.9-1.2 m (3-4 ft) wide, with individual leaves reaching up to about 60-90 cm (2-3 ft) long.

Watch for — Yellowing leaves and mushy stems: Usually overwatering or cold, especially when the plant is slowing for dormancy. Cut back on water in autumn/winter and check the corm and roots for rot.

How to tell colocasia 'illustris' (imperial taro) needs repotting

Repotting on a calendar is less reliable than reading the plant. For colocasia 'illustris' (imperial taro), watch for these signs:

Flowering has tailed off year on year and the clump has become congested and overcrowded.
Lots of leaf and few flowers — a classic sign that colocasia 'illustris' (imperial taro) bulbs or tubers need lifting and dividing.
Bulbs visibly bursting the pot or pushing each other to the surface.
It is the natural dormancy window (foliage yellowed and died back) — the only safe time to lift and split.

For the underlying biology of a pot-bound root system and why it stalls a plant, see our guide to spotting and fixing a root-bound plant.

How often to repot colocasia 'illustris' (imperial taro)

Lift and divide every 3–4 years once clumps congest. Rather than a true repot, colocasia 'illustris' (imperial taro) is lifted and divided once the clump congests and flowering drops off. Clumping, tuberous (corm-forming) perennial with bold upright stalks holding large, downward-pointing heart-shaped leaves; spreads by offset cormels..

What size pot to step colocasia 'illustris' (imperial taro) up to

Pot size matters less than depth and spacing here. When you replant colocasia 'illustris' (imperial taro), set the bulbs or tubers at the correct depth (a rough guide: two to three times their own height of soil over the top) and space them so they are not touching. A wide, shallow pot suits a clump better than a tall narrow one.

Not sure of the exact diameter? Our pot size calculator takes the current pot and root spread and tells you the right next size — it deliberately recommends a single step up, never a big jump.

The best time of year to repot colocasia 'illustris' (imperial taro)

The only safe window is dormancy: wait until the foliage has yellowed and died back naturally, lift and divide then, and replant before or at the start of the next growing season. Disturbing colocasia 'illustris' (imperial taro) in full growth or flower sets it back badly.

Step-by-step: repotting colocasia 'illustris' (imperial taro)

Wait for dormancy. Let colocasia 'illustris' (imperial taro) foliage yellow and die back completely. Lifting while it is in growth wastes the energy it is storing for next year.
Lift carefully. Loosen the soil well away from the bulbs/tubers with a fork and ease the whole clump out without spearing them.
Separate the offsets. Gently pull the clump apart into individual bulbs or tubers. Keep only firm, healthy, blemish-free ones.
Replant at the right depth. Reset them in fresh rich, humusy, moisture-retentive potting mix at the correct depth and spacing — not touching — so each has room to bulk up.
Water in and rest. Water once to settle them, then keep on the dry side until growth resumes. Do not feed until leaves are actively growing.

Aftercare

After replanting colocasia 'illustris' (imperial taro), keep the soil barely moist — not wet — until shoots appear; bulbs and tubers rot in cold, saturated soil. Once leaves are growing strongly, resume normal watering. Hold off feeding until the plant is in active growth again.

The right soil mix for colocasia 'illustris' (imperial taro)

Colocasia 'Illustris' (Imperial Taro) wants rich, humusy, moisture-retentive potting mix. Use a fertile, organically rich mix that holds moisture; adding compost or coir improves water retention. It tolerates and even enjoys boggy conditions, so heavy, water-holding media suit it. Ensure the pot still drains so the corm does not sit in stagnant, airless water indoors. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting colocasia 'illustris' (imperial taro) — frequently asked questions

How often should you repot colocasia 'illustris' (imperial taro)?

Lift and divide every 3–4 years once clumps congest for colocasia 'illustris' (imperial taro). Colocasia 'Illustris' (Imperial Taro) is lifted and divided, not "repotted". Every 3–4 years, once the foliage has died back and it is dormant, lift the clump, separate the offsets, and replant at the correct depth in rich, humusy, moisture-retentive potting mix. Crowding, not pot size, is what reduces flowering over time.

What size pot does colocasia 'illustris' (imperial taro) need?

When is the best time of year to repot colocasia 'illustris' (imperial taro)?

Do you "repot" colocasia 'illustris' (imperial taro), or lift and divide it?

You lift and divide it. Colocasia 'Illustris' (Imperial Taro) grows from bulbs or tubers, so instead of repotting you wait for dormancy, lift the congested clump, separate the healthy offsets, and replant them at the right depth and spacing. Doing this every 3–4 years restores flowering.

Should you fertilise colocasia 'illustris' (imperial taro) after repotting?

Hold off feeding colocasia 'illustris' (imperial taro) until it is in active growth again. Fresh soil already carries enough nutrients to get it re-established, and feeding disturbed roots too soon does more harm than good.