Posted: 06/04/2013 at 09:16
I have heavy clay - the hellebores are loving it. I found some stuff called 'soil improver' that's pretty cheap, made from recycled garden waste, and well rotted manure can be obtained inexpensively. You could try applying it as a mulch round the base of the plants to keep it from the edges, but building up the height of the bed will improve drainage.
I am a novice and still learning but I have one piece of advice - avoid adding sand. We've just cleared a patio and gravelled area that had been levelled with sand and some parts had turned into something concrete - like!