A tall wiry much branched perennial with sparse foliage and topped by a large delicately scented head of lilac-purple flowers that attract butterflies and other insects. It will self seed freely and often finds much better plant associations than you or I could, running it through a cottage border or mixed in with 'exotics' - it looks superb either way. 1.8m (6ft).
Upright clump-forming perennial, producing stiff panicles of pinkish-purple flowers from early summer and into autumn. Full sun & well drained soil. 120cm (4ft).
Slowly spreading perennial, forming a mat of hairy toothed leaves, in summer it is covered in upright branching spikes of fragrant, brilliant purple flowers. Needs a sunny dry spot with summer moisture at its roots. 30-45cm (12-18").
If you want a really intense, deep blue flower, then you can do no better than this plant. Each flower is clustered together with many others in erect terminal spikes, that are produced in early summer. Underneath this display are neat ovate leaves, toothed along their margins - forming a pleasing dome. 30cm (12").
A charming mat-forming evergreen perennial, with broad, lance-shaped leaves of a shiny dark green colour, in late spring to early summer pale sky-blue flowers in erect racemes 30cm (12") high rise above
This native of Eastern North America has very tall, airy spires of beautiful pale pink-white flowers from June onwards; surrounding the lower portions of each flower stem are whorls of leaves. Requiring a good to moist soil in sun or shade. 1.5m (5ft).
A selection with rich lilac-violet coloured tapering flowers, held on reddened stems, all set against the dark foliage, having a bold upright presence in the garden. Can be cut and used in flower arranging. 1.8m (6ft).
A miniature beauty. Flowers are rich creamy-apricot and scented - produced in early spring.