While not native to SC PA, blue false indigo or wild blue indigo (Baptisia australis) is found scattered throughout the state and much of the Mid- and Eastern-US. It has blue-green folliage and tall spikes of purple flowers in May and June. The plant will get 3-4' tall and wide, almost like a shrub. It can be trimmed up after blooming, but then you sacrifice the black seed pods that provide interest the rest of the year.
False indigo can be grown in full sun to part shade in well-drained poor soils. It is rabbit resistant and drought resistant. They are slow to get established, but once they are, the extensive root system that allows them to grow in adverse conditions also makes them really tough to transplant, so choose your planting location wisely!
Other varieties of indigo (Baptisia) have white, yellow, or deep purple flowers.
Source: Missouri Botanical Garden
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