Commonly known as sea holly plants, Eryngium are striking, exotic-looking perennials with spiky, thistle-like blue, violet or silvery blooms with cone-like centres produced on green or silvery-blue stems. The flower cones are adorned with a ruff of jagged, showy bracts, perfect for adding colour and interest to your garden throughout summer and autumn. Sea hollies typically have an upright growth habit with spiny-toothed leaves, reaching around 45-90cm tall, making them well suited for the front or centre of mixed and perennial borders. Versatile and unfussy, they are drought tolerant, will withstand salt-laden air in coastal gardens and cope with wind and/or sandy soils. Their steely blue flowers work well as a calming influence alongside red and yellow flowering perennials. Native to Europe and the Mediterranean, they're perfect for attracting butterflies into the garden and make excellent cut or fried flowers. Dead head spent flowers to encourage more fresh blooms.