Don't use dog daisies they wilt just talking about it. Why not cannibalise a couple of hedgerows - can't get tougher or more natural than that. This time of years a lot has gone over to berries but you can get some great textures and then use things that might be in the garden now - leaving out xanths - some rose hips, lavender, heather, unfortunately everything delicate has nearly gone. Asters?

Dying to see the pic