Liatris are easily grown, reliable herbaceous perennials, surprisingly rarely seen. Known in their native North America as gayfeather or dense blazing star (and also as button snakewort, which seems to me to have three incorrect descriptions in just two words!), they have dense, narrow spikes of flowers of the form commonly described as like a bottle brush - but when did you last see one of them? Imagine small thistle flowers packed together, and you won’t be far wrong. They are attractive to bees.

Liatris spicata 'Alba' is a form with spikes of white flower heads, which appear in mid-summer above the grassy, pale-green foliage.