Acanthus hungaricus (Long-leaved bear's breeches): Architectural spires of purple/white flowers over large, dark green deeply divided leaves. Best in sun or light shade. Height to 1.2m [Collect Only]

Baptisia 'Purple Smoke' (Indigo weed 'Purple Smoke'): Tall spikes of violet pea-like flowers on almost black stems, attractive grey-green foliage. Dark-grey seed pods. Hardy. Up to 1.2m

Centaurea 'Jordy' (Perennial cornflower 'Jordy'): Beautiful maroon-purple flowers over felty silvery-green foliage.

Centaurea montana 'Parham' (Perennial cornflower 'Parham'): Large lavender purple fluffy flowers over silvery-green foliage. To 40cm. Hardy

Geranium pyrenaicum 'Bill Wallis' (Mountain cranesbill 'Bill Wallis'): Masses of tiny purple flowers, good for ground cover

Geranium wlassovianum: Warm purple flowers over attractive velvety foliage. Excellent autumn foliage colour.

Lathyrus vernus (Spring pea): Two-tone purple and pink pea-like flowers in early spring. Thrives in shade, even quite dry shade. To 30cm. Hardy.

Liriope muscari 'Big Blue' (Blue turf lily 'Big Blue'): Spikes of vibrant purple flowers in autumn, larger than the usual form, evergreen strappy foliage. Good for dry shade. Hardy. Up to 50cm

Perovskia 'Blue Spire' (Russian Sage 'Blue Spire'): Fine spikes of purple flowers on silver stems. Lovely winter stem effect. Hardy. Up to 1m.

Pulsatilla vulgaris 'Papageno' (Pasque flower 'Papageno'): The petals are deeply dissected, giving a frilled, double effect. Usually purple but can be pink, reddish or white. Hardy. To 30cm

Verbena bonariensis: Tall, airy but strong slender stems with flat heads of purple flowers in mid to late summer. To 1.8m. Frost-hardy. [Collect Only]