Q Why do the leaves on my water lilies yellow so quickly?
Graham Newsam, Little Shelford, Cambridgeshire
AIt’s important to appreciate that water lilies produce leaves in succession during the summer that age and die. You need to remove them, along with the spent flowers, every now and again. I’ve noticed at RHS Wisley that the water lilies in the canal in front of the main building have yellowed rapidly this year and wonder if it’s anything to do with the hot weather in June. Other causes of leaves yellowing prematurely include where plants are too deep in the water. It’s essential that the particular variety is matched to the depth of the water. It’s also important to place baskets of newly-divided water lilies on bricks and gradually lower the container into the water in stages.