North American prairie native with deep blue lupine-like flower spikes in late spring. Long-lived and architectural — a permanent garden feature once established.
Hardiness ratings
| System | Rating | Temperature range | How to read it |
|---|---|---|---|
| USDA hardiness zone | Zone 3–9 | −40 °C to −1.1 °C | Plant tolerates down to this zone |
| RHS hardiness rating | H7 | down to −20 °C | Plant needs at least this level of cold tolerance |
| Canadian plant hardiness zone | Zone 3–9 | −34 °C and warmer | Plant tolerates down to this zone |
| Australian (ANBG) zone | Zone 1–5 | −15 °C to 10 °C | Plant tolerates down to this zone |
Growing notes
- Deep taproot — do not transplant once established; sites for life
- Long lived (decades) and exceptionally drought tolerant
- Major host plant for several Lepidoptera species
Categories
Related plants
Cross-check False indigo (Wild blue indigo) against your zones