Posted: 20/08/2015 at 08:27
They've been neglected I suspect or perhaps were unsuitable for soil or aspect.
I'm on clay too have to be careful on choice of grasses. Look up carefully what best suits your soil, moisture and aspect and yours should do much better. I have miscanthus in the sunny area and hakleokena in the damp part shade.
I like tall daisy like flowers with grasses eg rudbeckia, echinacea, helenium - depending on what the site is like.I'm also a big daylily fan - they do well on clay.