The RHS Chelsea Flower Show may not have happened this year but we can still think of it while we prune back our late flowering herbaceous plants to avoid them getting too leggy. By removing the top shoots, and cutting the plant back by around a third, the side shoots branch out making the plant more compact and the flowers smaller but more numerous and later to bloom. Alternatively if you have lots of clumps of the same plant why not cut back some plants, or even only a few stems on the same plant, to stagger your flowering season.
Perennials such as sedum, nepeta or phlox should be cut back by around June, although later flowering perennials such as astrantia and penstemon can be cut back as late as July for a second flush.