If I may ask another question coz your knowledge is ace!!
I have a postage stamp sized garden with a few borders. It's north facing (argh!) and sadly a garden that has flood problems too due to previous owners building over damp proof. As we have to lower the entire garden, I wanted to put cream/buff limestone all over where the paving slabs are now, and just keep my boarders that I fill to the brim with flowers and veg. White being to help brighten up the area for all the plants and limestone chippings to let the water flow freely away.
My neighbour informed me that her white stones (do not know what type) discoloured really quick and went green. Anyone had any experience/regrets or advice over pale stones? I have my heart set on it, but obviously if a really bad idea I will rethink!