This upright, prickly, herbaceous perennial provides valuable architectural interest from midsummer to autumn, when a lot of other border plants are past their best. It grows to around 3ft (36in), producing branching stems of violet-blue flowers with narrow, grey-blue bracts, and is good for using indoors as a dried flower.

Sea holly thrives in full sun, in poor, dry soil, which is why it does so well at the seaside. It may need protection from excessive winter wet, especially in an exposed garden. The most popular taller type is E. oliverianum, but you can also get low-growing ones including the evergreen E. variifolium, which grows to 60cm (2ft) and E. alpinum, with metallic blue flowers.