For the second year in a row, after the first lush blooming of my 8-year-old "Mayflower" it's stopped blooming and the leaves are quickly turning yellow. Last year I thought I could solve this by simply deadheading, but that appeared to traumatize the plant further -- it faded away to nothing until early this spring.

Any thoughts? We've just had a week of unseasonably hot weather -- could it simply be needing some H2O?

Many thanks.