Potted planted will always need double the amounts of water - are you watering copiously twice a week ?

I have a hibiscus here and it flowers okay, it's in a warm and sunny site and on alkaline soil.

Another thought ..... yours wouldn't be in too small a pot would it and need repotting ?
A plant the size of a hibiscus will need a pot that's at least 2' deep and 2' diameter and then repot it every 2 or 3 years to larger ones all the time - it would prefer to be in the ground really though.

Could you be specific about which Hibiscus you have?

H.rosa-sinensis for example is an indoor plant. This needs a bright spot, regular watering and misting. A 25cm tomato pot is ideal.

I bought two from Thompson and Morgan earlier in the year. They are in large, identical pots each in the same sunny position. One is doing fine, the other hasn't a sign of a leaf. Perhaps they are just really difficult plants.

Thank you everyone. My hibiscus is syriaca Duc de brabant and flourishes on the hillside at Bodnant. I bought it in August 2009 and yes it could have outgrown its pot. I do water and feed it regularly with Miracle Grow. Last winter I brought it into the conservatory for the winter - luckily as iIlost so many plants hebes, ceanothus, all the fuchsias kept in the shed etc
Derrickdunkley

Sue has two very similar ones which are planted in the ground up against the kitchen wall - came through the last two winters unharmed.