Delphiniums are tall plants with dense clusters of blossoms on top of a flower stem surrounded by deeply lobed leaves. These flowers are white to any shade of blue or purple. Delphiniums should be planted near the back edge of flowerbed because they will overshadow any plant behind them.
Delphiniums blossom from late spring throughout the summer. Cut old flower stalks to encourage a second bloom in autumn.
Delphiniums grow from 4 1/2 to 6 feet tall and 2 to 3 feet wide.
Delphiniums like compost-rich soil with good drainage. They prefer full sun, but like the soil moist.
Plant delphinium seeds in the spring or fall. Divide overgrown plants in the spring. Plant these divisions right away.
Delphiniums suffer from powdery mildew. Dust plants with sulfur if you notice white blotches on the leaves.
Delphiniums are highly toxic if eaten. Symptoms include burning of mouth, numbness of throat, vomiting, diarrhea, muscle spasms, paralysis of respiratory system, convulsions and death.