Description:
Eryngium is a genus of about 230 species of annuals and perennials with hairless and usually spiny leaves, and dome-shaped umbels of flowers resembling those of thistles. The genus has a cosmopolitan distribution, with the centre of diversity in South America. Some species are native to rocky and coastal areas, but the majority are grassland plants. Common names include Sea-holly and Eryngo, the former typically being applied to coastal species, and the latter to grassland species.
The flowers are clustered in tight umbels, with a whorl of spiny basal bracts.
Eryngium maritimum is a perennial plant native to Europe and often found on sea shores. It produces a basal rosette, from which grow flowering spikes with stiffly spiny foliage and stems. These can reach around 50 cm in height. It is often grown in gardens for its metallic bluish flowers and upper foliage. The basal foliage is a very conspicuous pale grey or silvery green, from which the stiff, lightly-branching flowering stems rise up.
Related species are grown as ornamental plants in gardens, and these may also be called "sea holly", though the majority are not associated with littoral (sea-shore) habitats. Among the best known of these is Eryngium bourgatii (illustrated), a perennial with stunning green, prickly foliage marbled with silver. The flowers, which appear in summer, are cobalt blue, and very attractive to bees. The plant is 30 to 60 cm in height. Other commonly grown ornamental species include Eryngium alpinum, E. variifolium, E. tripartitum, E. bromeliifolium, and the biennial E. giganteum.
Uses
Many species of Eryngium have a history of use. The roots have been used as vegetables or for sweetmeats. Young shoots and leaves are sometimes used as an asparagus substitute. The roots, such as of Eryngium yuccifolium and Eryngium maritimum, are potent inflammation modulators and may have other properties.