Blue Delphinium Flowers

Identification

• Delphiniums' most noticeable aspect is their tall, showy flower spikes. Dozens of small individual blossoms, each backed by a single spur cover the elongated spikes. Although most delphiniums are blue, many cultivars have purple, yellow, white, pink or red blooms. The plants range in size from 1 to 8 feet tall with an approximate 3-foot spread. They have palmate-lobed leaves, or deeply divided leaves shaped like the palm of a hand.

Cultivars and Species

• Delphinium grandiflorum plants grow about two feet tall. D. grandiflorum "Blue Elf" is a blue-flowering compact variety; Blue Butterfly and Blue Mirror both yield deep-blue flowers. D. x belladonna "Cliveden Beauty" hybrids produce pale-blue blossoms, while the flowers from D. x belladonna "Bellamosa" are a deep-blue color. D. semibarbatum "Blue Springs" yields blue or sky-blue flowers. Other blue cultivars include Black Knight, which has midnight-blue flowers and Summer Skies with blue and white flowers. (see references 1, 4, 6)

Blue Delphinium Care

• Most delphinium plants produce their showy blue blossoms between the beginning and middle of summer. Removing the flower stalks as soon as the blossoms are spent encourages delphinium plants to produce more flowers later in the season. Plant delphiniums in neutral or alkaline, well-draining, nutrient-rich, moist soil and full sunlight for best results. They benefit from monthly fertilization. Water delphiniums one or two times a week during dry weather. Stake tall cultivars, since some varieties have a tendency to droop. Delphiniums usually last between 2 and 3 years.

Pests and Problems

• All parts of the delphinium plant contain toxic alkaloids and can cause death if eaten. Victims experience burning around the mouth, nausea, respiratory paralysis and a shallow pulse, eventually followed by seizures and death. Plants growing in poorly drained soil are susceptible to root rot. Powdery mildew, a fungal infection, leaves powdery white areas of fungal growth on the leaves, while leaf spot infections create unsightly spots on the foliage. Slugs chew holes in the leaves, while mites and aphids drain sap from the plants.