Lupine has unsurpassed early summer color with dense spires of pea-shaped flowers. These plants prefer light, well-drained soil that is slightly acidic, and they do not tolerate heat or humidity well. It performs best in areas with cool summers. Deadhead old flowers to promote rebloom. The lupine plant fixes nitrogen in the soil and is a great addition to your vegetable garden or any area where nitrogen loving plants will be grown.