Helianthus 'Monarch':
A perennial sunflower with tall, semi-double bright yellow flowers. Prefers a sunny spot. Flowering late summer. Hardy. Up to 2.5m.
Salvia uliginosa (Bog Sage):
Branched stems of clear blue flowers and lance-shaped leaves. Needs a sunny spot but with moist soil. Hardy. Up to 2m. AGM.
Sanguisorba canadensis (White burnet):
Bottle-brush white flowers in late-summer above green pinnate foliage. Very tactile plant. Long flowering. Hardy. Up to 2m