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]

Centaurea montana (Perennial cornflower): Large blue flowers in early summer, repeated later in year if cut back. Very attractive to bees. To 50cm. Hardy

Centaurea montana 'Grandiflora' (Perennial cornflower 'Grandiflora'): Larger blue flowers than the species, with darker purple heart in early summer, cut back for repeat flowering. Very attractive to bees. To 50cm. Hardy

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

Nepeta 'Six Hills Giant' (Catmint 'Six Hills Giant'): A vigorous sun lover which will soon make a generous clump. Spikes of tiny purple flowers over aromatic grey/green foliage.

Sisyrinchium striatum: Open fans of strappy iris-like leaves topped with lemon yellow flowers in summer. [Collect Only]