Sea Holly is an interesting xeric plant family (Eryngium), especially if you are looking for striking blue-purple flowers. Although not true hollies, the cones look similar. They have a distinctive bract collar which adds great interest.

The blue cones are large and tend to have a shiny sheen. Stems are silvery blue too. However, only a few varieties are adapted to the Front Range, and tolerant of drought, high winds, cold, and heat.