Dianthus cruentus (Blood pink):
Deepest red flowers held on airy stems above grassy foliage. Thrives in poor, well drained soil in full sun. Dislikes wet, cold, heavy soils.To 60cm.
Lychnis chalcedonica (Maltese cross):
Domes of bright scarlet flowers with four petals, hence its common name. Excellent for adding height and bright colour in summer borders
Sanguisorba tenuifolia 'Purpurea':
Tall dark-red purple bottle-brush flowers over fine, frondy foliage. Likes sun or dappled shade, not too dry. To 1.5m Hardy.