(C. elata x C. flexuosa) The first of these hybrids this is a good tough plant. More or less evergreen, fresh green foliage produces upright stems topped with big heads of bright blue, scented flowers in mid-late spring. 50cm. Good soil in shade.
Larger than normal blue-mauve flowers on this hardy Impatiens for decent soil (not wet) in shade. Can be quite late up but flowers sooner than some other hardy species. 60cm.
Neat clumps of upright foliage and pretty sky blue and white flowers to c. 50cm. Good soil in sun. From Beth Chatto as Iris spuria ssp halophila but it isn't!