Growing colocasia Black Coral

I grow them Verdun.

I keep them in really big containers, 75L just on the limit on what I can lift. Once in active growth they need lots of water (I stand mine in big saucers and keep them tooped up), a very sunny position and regular feed of high nitrogen food. The wind gets at my bigger ones and so I trim off ragged leaves, new ones are constantly produced.

Winter is the biggest challenge for me, as they are obviously frost tender. I've tried letting them go dormant and starting them into growth in the spring but generally the tubers rotted off. What works for me is to move them into a heated greenhouse overwinter, and remove most leaves. Kept at 5C and fairly dry they remain in leaf through winter, although looking very sorry by spring. Like cannas they grow like crazy when the warmer days return pushing up new buds.

C esculenta with granddaughter for scale:


This showing the pot:


And Black Coral, doesn't get as big as the green ones - has a metallic sheen:

 

Not sure if that helps you Verdun, what were your problems this year?

 

The method I used to start off the dormant corms was to put them in a poly bag and blow in - apparently one breathe is enough moisture to trigger them into growth (after a few weeks). I got that method from another forum. About 50% of the ones I tried like this rotted off so it's very hit and miss. People soak them in a dilute bleach first and other concoctions, it seems a black art to get out of dormancy (hence why I try and keep mine in growth all year round). You can buy them in Asian supermarkets for next to nothing, called taro but they don't have the big leaves - good for practising on though.

They should be OK over winter in your conservatory over winter.