Asphodeline lutea (Asphodel):
Vertical spikes of sulphur yellow flowers in early to mid-summer. Hardy, but dislikes heavy soil in winter. To 1.2m
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.