Delphinium andersonii A.Gray
Delphinium andersonii subsp. andersonii, Delphinastrum andersonii, Delphinium cognatum, Delphinium megacarpum, Delphinium scaposum var. andersonii, Delphinium tricorne var. andersonii
Color: Dark blue
Bloom Time: Summer
Delphinium andersonii is an erect perennial plant that grows up to 20 inches (50 cm) tall. It has small leaves on long petioles with the leaf blades divided into long finger-like lobes. A cylindrical inflorescence of flowers occupies the top of the slender stem. Each flower is up to 1.6 inches (4 cm) across, with an up to 0.8 inches (2 cm) long spur. The flowers usually have sepals of a brilliant dark blue, with the lower two petals the same color and the upper two petals white. Some specimens have sepals and petals of very light purple or blue to almost white. The anthers are often yellow.
USDA hardiness zone 3a to 8b: from −40 °F (−40 °C) to 20 °F (−6.7 °C).
How to Grow and Care
Grow Delphiniums in a sunny area with consistently moist soil. Don't let them dry out. Mulch helps retain moisture and keeps roots cool. The performance of this specimen is enhanced when growing Delphinium plants in neutral to slightly alkaline soil pH. Soil should be well-draining.
Care of Delphinium should include regular fertilization in spring when the plant begins to grow and during the flowering period. Work in well-composted organic material such as rotted cow manure, or use a basic 10-10-10 granular fertilizer. Yellowing foliage or stunted growth often indicates the plant needs more fertilizer.
Sun exposure is another aspect of care of Delphinium that the gardener must get right for the showy blooms to appear. Gentle morning sun is preferable to the Delphiniums, which are picky about extreme differences in temperatures. Provide afternoon shade, especially when planted in hotter zones.
See more at How to Grow and Care for Delphinium Plants.
This species is native to western North America, found in the Great Basin and the Sierra Nevada.
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