Lychnis coronaria also called Rose Campion and Eryngium ‘Superbum’ or Sea Holly blend well together in this late summer photo.The colour combination may be a bit too Barbara Cartland for some tastes.

Eryngium like Echinops have spiky leaves and bristly metallic blue flowers that make it a great architectural plant. The grey green unassuming leaves of Lychnis belie the strength of colour of their flowers.

Salvias are available in a range of colours including reddish blue. I might have been tempted to partner with the insignificant but highly aromatic Night scented stocks for this photo