Limonium binervosum

Limonium binervosum, commonly known as rock sea-lavender, is an aggregate species in the family Plumbaginaceae.
Despite the common name, rock sea-lavender is not related to the lavenders or to rosemary but is a perennial herb with small violet-blue flowers with five petals in clusters.
Eight rock sea-lavenders are endemic to Britain and Guernsey and the taxonomy was reviewed in 1986 to include a range of subspecies.
Growing 10–70 cm tall from a rhizome, "Limonium binervosum" flourishes in saline soils, so are therefore common near the western coasts and in salt marshes, and also on saline, gypsum and alkaline soils such as found on Flat Holm island in Wales, UK