Centaurea dealbata (Persian cornflower): Large, showy pink flowers over deeply divided foliage. Makes a good-sized clump in a couple of years. To 60cm. Hardy. [Collect Only]

Centranthus ruber 'Albus' (White Valerian): White panicles of white flowers in mid-late summer. Very easy, self-seeds. Perennial and hardy. To 60cm.

Tradescantia (Andersoniana Group) 'Osprey' (Spider lily 'Osprey'): Three-petalled white flowers with a fluffy blue centre above strappy foliage. Great as a ground clump former in sun or part shade.

Tradescantia (Andersoniana Group) 'Red Grape' (Spider lily 'Red Grape'): Three-petalled large, reddish-pink flowers above strappy green foliage. Great as a ground clump former in sun or part shade. Hardy. Up to 50cm.