Globe thistle. Wooly stems with spherical dark blue flowers in midsummer and prickly divided green leaves. Looks wonderful in bold drifts and  towards the back of mixed perennial borders. Any ..

Spiky electric blue flower heads on silvery stems above divided silvery green leaves. Any soil. Best in sun. Height and spread to around 1m x 45cm.    ..

Prickly deeply cut greyish green leaves with white globe flowers on maroon stems to 80cm tall from mid to late summer. Best in fertile, free draining soil in sun or part shade.   ..