These hardy perennials, commonly known as Sea Holly or Eryngo, are natives of the damp grasslands of South America. They grow from 5 to 6 feet high and spread up to 2 feet. They produce evergreen, sword-shaped, gray-green leaves that have spines at the edges. In late summer they produce small, rounded flowers, resembling thistles, on branched stems. The dried flowers are very useful for winter arrangements. Cut them before they are completely open. The flowers of Eryngium eburneum are green with white stamens, those of Eryngium alpinum are light blue, and those of Eryngium amethystinum are pale violet blue. Others will be mentioned below in the varieties section.

Sea Hollies like light, well drained sandy loam in a warm, sunny position. If your soil is heavy, dig and mix sand, grit and compost into it. These plants don't like to be disturbed, so they should be set in their permanent position.

Sea Hollies may be increased by sowing seeds in the fall, division in the spring, or by root cuttings in the winter, which are inserted in boxes of light compost.

Eryngium eburneum (F. green & white);
Eryngium alpinum (F. light blue);
Eryngium amethystinum (pale violet blue);
Eryngium giganteum (L. light gray; F. same);
Eryngium Bourgatii (F. light blue);
Eryngium planum (steel blue);
Eryngium Violetta (purple blue);
Eryngium tripartitum (F. bright blue);
Eryngium Oliverianum superbum (F. pale violet) ;
Eryngium maritimum (L. gray; F. light blue);
Eryngium aquaticum (This native of NEryngium U.S. is sometimes grown & is commonly called Button Snakeroot.).