Achillea ptarmica 'The Pearl' (Yarrow 'The Pearl): Tight buttons of white flowers, ferny grey/green foliage. Prefers full sun and light well-drained soil. Hardy. Up to 60cm.

Agastache rugosa f.albiflora 'Liquorice White' (Korean mint 'Liquorice White'): Tall, aromatic perennial with spires of tiny white flowers. Aromatic foliage. To 1.5m. Fully hardy in light soils. May self-seed.

Armeria maritima 'Armada White' (Thrift 'Armada White'): An old fashioned cottage garden favourite. Makes a neat clump of evergreen foliage with white pom-pom flowers suffused with pink. Hardy. Height to 20cm.

Catananche caerulea 'Alba' (Cupid's Dart (White)): Papery white flowers above slender grey-green foliage. Flower heads retains attractive form through winter. To 60cm. Hardy

Cenolophium denudatum (Seseli libanotis, Baltic parsley): Flat umbels of pretty white flowers in summer. Fine, filigree foliage. Great in borders, sun or part shade. Hardy. To 90cm

Centaurea montana 'Alba' (Perennial cornflower - white): Large white cornflower-like flowers over grey-green foliage. To 30cm. Hardy.

Centaurea montana 'Purple Heart' (Perennial cornflower 'Purple Heart'): Large white cornflower-like flowers with violet central markings. To 30cm. Hardy

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

Ligusticum scoticum (Scottish Lovage): Native plant with white umbels above mound of green leaves. Celery like leaves. Up to 60cm. Hardy

Verbena hastata 'Alba' (American blue vervain 'Alba'): Tall, branched stems like a candelabra with spikes of small white flowers loved by bees. Needs a sheltered spot & full sun. Up to 1.2m.