Alchemilla mollis (Lady's mantle):
Bright green soft leaves and a froth of acid yellow/green flowers in summer. Very easy for ground cover. Height to 30cm.
Cephalaria gigantea (Giant scabious):
Very tall wavy stems topped with large lemon yellow scabious-like flowers. Easy to grow. May need staking or support. Hardy. Up to 2m.
Crocosmia 'Hellfire':
A tall variety with vibrant red flowers with a darker red thoat above strappy green leaves. Hardy. To 1.2m.
Crocosmia 'Lucifer':
Swathes of brilliant scarlet flowers over bold strappy green foliage. Easy and trouble free as long as soil is not too wet. To 1.2m. Hardy.