Eryngiums are also known as sea holly: they grow well in coastal areas and have spiny leaves and a characteristic ruff around the flowerheads.
The thistle-like flowers are made up of tiny flowers packed together in a tight cluster. With colours ranging from grey to intense cobalt blue, eryngiums are striking plants. There are over 250 species and lots of garden cultivars to choose from. They look wonderful in gravel gardens or mixed herbaceous borders and they’re good for attracting pollinating insects.