Calamintha nepeta 'White Cloud':
Spikes of small white flowers above mounds of minty scented green leaves. Loved by bees and butterflies. Hardy. Up to 30cm.
Gaura lindheimeri 'The Bride':
Beautiful airy stems of white flowers in mid to late summer. Best in full sun, in well drained soil and a sheltered spot. Stems up to 1m.