Molinia caerulea 'Heidebraut' (Purple moor grass 'Heidebraut'): Elegant flower stalks with slender purple flower heads in late summer. Makes an upright, vase shape. To 1.2m. Hardy

Veronicastrum virginicum 'Lavendelturm' (Culver's Root 'Lavendelturm'): Long, narrow spires of tiny, pale lavender-blue flowers above whorls of narrow, dark green, serrated leaves. Tall to up to 2m.