Baptisia australis, False Indigo

Blue false indigo, Rattlebush
Baptisia australis

Hardiness: Zones 3 to 9
Plant type: Herbaceous perennial
Height: 3- 4'
Spread: 3- 4'
Sun: Full sun to part shade
Water: Dry to medium
Bloom time: May, June
Bloom color: Indigo blue
Soil: Prefers acidic soils, clay and well draining, adaptable

Notes: Attracts butterflies, tolerates drought, and poor and rocky soils.

More information on this plant here.