Thanks for commenting. Surely you should try Eryngium yuccifolium, the rattlesnake master native to the eastern 2/3rds of North America. Very tough, durable, and long-lived. Great silvery color. There are other native eryngos, but this would be the most readily available. You could also try other cultivars of E. planum. Friends of mine grow a lovely cultivar called ‘Blue Glitter’ that looks nice. Ken Druse mentions ‘Blaukappe’ (Blue Cap) in his comment above. Though I’ve killed the first two I tried, ‘Jade Frost’ glows with creamy pink variegation that most prominently displays during cool nights (ie-spring and fall for best show). Enjoy eryngos!