Heuchera 'Black Pearl':
Dark purple almost black leaves with ruffled edges and white flowers. Does fine in sun or dappled shade. Hardy.
Hosta 'Devon Green':
Elegant hosta with tapering, dark green, fine-veined leaves. Lilac flowers in summer
Thalictrum delavayi (Chinese meadow rue):
Dainty lilac-mauve flowers 2cm in width, with prominent creamy yellow stamens above fern-like bright green leaves. Hardy. Up to 1.5m.