Delphinium — 11 species

Delphiniums are bold, cottage-garden perennials and biennials prized for their towering spikes of blue, purple, white, or red flowers — exemplified by Candle larkspur, Siberian larkspur, and the rich-scarlet Red larkspur. They thrive in full sun with at least six hours of direct light daily and prefer consistently moist, fertile, well-drained soil; water at the base to protect foliage. All Delphinium species are toxic to cats and dogs: the alkaloids they contain cause muscle weakness, tremors, excessive salivation, and, in serious cases, respiratory failure. Keep these plants well out of reach of pets.