Eryngium yuccifolium, Rattlesnake Master

Rattlesnake master
Eryngium yuccifolium

Hardiness: Zones 3 to 8
Plant type: Herbaceous perennial
Height: 3- 3.5'
Spread: 2- 3'
Sun: Full sun
Water: Dry to medium
Bloom time: June to September
Bloom color: Greenish white
Soil: Clay-based, moist, organically rich soils, loamy, average well-draining soils, sandy, well-draining soils, neutral (≈7), alkaline (>7pH), acid (<7pH).

Other notes: The blooms are attractive to butterflies and other insect pollinators.

More information on this plant here.