Genus: Sea holly

Eryngium

Photo/Illustration: 
Michelle Gervais
Sea holly (Eryngium)
air-ING-ee-um
Apiaceae
Plants in the genus Eryngium are characterized by spiny basal rosettes with conspicuous white veins. Rounded nubs of thistle-like flowers are borne on branched stems.
Noteworthy characteristics:  Wonderfully sculptural accents with icy blue to ghostly silver toothed bracts and flower heads, which persist for a long time.
Care:  Depends on species, either dry or wet soil, in full sun.
Propagation: 

Sow seed in containers when ripe, divide plants in spring (plants are slow to recover).

Problems: 

Root rot, slugs, snails and powdery mildew.