Zantedeschia aethiopica 'Crowborough' arum lily - Unusual, pure white hood-shaped flowers that are up to 10-15cm (4-6in) long are produced from late spring to mid-summer. It makes a striking architectural clump with lovely arrow-shaped, glossy dark green leaves. It looks great grown beside water as a marginal plant and can be left outside in most frost-prone areas if it is given a deep winter mulch.
Acanthus spinoffs - armed bear's breech - a handsome herbaceous perennial to 1.2m, with large, deeply lobed and spine-tipped, dark glossy green leaves. Erect spikes of white flowers with spiny purplish bracts in late spring and summer