For partly shaded sites, my one of my favourite herbaceous perennials is the graceful meadow rue Thalictrum delavayi. It flowers through summer and even sometimes into early autumn. It arises to about 1 m (or more) from a basal clump of pretty, lacy foliage rather reminiscent of a large maidenhair fern and has clouds of tiny quivering flowers of pale purple with prominent stamens. There is a rare white cultivar, called 'Album'. The plants may need support from cradle stakes or surrounding shrubs when in bloom. Thalictrum make good cut flowers for vases.
It self-seeds where it finds a garden bed to be of its liking (it enjoys rich, well-drained soil and ample moisture) and is such a pretty companion to other part-shade lovers, such as ferns, Begonia and Justicia species. Its range is from East Tibet to West China and it belongs to the Ranunculaceae family of plants, which includes Aquilegia, Helleborus, Clematis and Anemone. Propagation can be achieved by division of the clump in winter when it is dormant.