Astilbe chinensis var. taquetii 'Purpurlanze': A very tall form with statuesque fluffy purple flowers above fresh green ferny foliage. Excellent for damp or shady spots. Hardy. Up to 1.2m.

Lobelia x speciosa 'Vedrariensis': Dramatic spikes of royal purple flowers in late summer. Needs damp soil in summer so is ideal for bog gardens. Height to 1.2m. Hardy

Lythrum virgatum 'Dropmore Purple' (Wand loosestrife 'Dropmore Purple'): Upright spikes of purple-pink flowers in the mid-summer with lance-like foliage. Prefers a moist soil. Hardy. Up to 1m.