Amsonia tabernaemontana 'Storm Cloud' forms an attractive clump of upright, near-black stems, which are woven along their length with slender, deep green leaves, each with a silvery white stripe that runs along its length. The leaves become paler as they mature, and then, in late spring and early summer, pointed buds open to dazzling blue star-shaped flowers.

Rarely affected by pests and diseases and a cinch to grow, it's a useful perennial that can be used to add colour and form towards the front of the border.