Can anyone help please. I moved into a new build house in Oct 18. The soil is heavy clay. Everything I have planted has survived after initial yellowing, but the euphorbias I have planted in one of the borders have all turned deep red. I am not sure that I would have expected this as in my previous gardens this variety would still be a lime green/yellow colour, awaiting dead heading! They would look lovely if it was autumn! Any ideas of causes or remedies would be very welcome.