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Growing Delphinium

Growing Delphinium

Butterfly Blue



Delphiniums are popular hardy perennials with attractive flowers. Available in Butterfly (Delphinium grandiflorum) types with a compact habit and masses of spurred flowers and tall forms with large flower spikes. Both types are hardy in zones 3 to 7. Delphiniums are excellent for producing masses of color, and tall types are good for background planting and cut flowers.

How To Plant

Plant in spring after the last frost, so that roots are just slightly deeper than in pots. Some types can be started from seed indoors 7 to 9 weeks before outdoor planting time. Plant seed 1/8 to 1/4 inch deep and maintain at 65 to 70 degrees. Expect germination in 10 to 20 days.


For full sun in well-drained soils. Prefers cool climates and benefits from afternoon shade in hot climates. Deadheading promotes reblooming. Plants are somewhat short-lived, especially in hot climates, and may need replacement every 2 to 3 years. Tall varieties benefit from staking or support, especially in windy areas.

Fertilizer Recommendations

Plants are moderate to heavy feeders and benefit from regular fertilization. Use full rates of ALGOplus Flowering Plant 4-6-7 liquid fertilizer, Neptune Fish & Seaweed Fertilizer 2-3-1, or Osmocote slow-release 14-14-14

Common Problems

Sometimes attacked by aphids, mites, snails, or slugs. Diseases including grey mold, leaf spot, and powdery mildew occasionally occur. Plants can suffer root rot if grown in heavy, wet, or poorly-drained soils. 

Alternative Products

Other perennials cut flowers include Daisy, Liatris, and Rudbeckia.

Product Recommendations

Use 20" Grow Through Plant Supports to keep plants upright in the garden. Sluggo Plus can be used to control slugs and snails. Use insecticidal soap to control aphids and mites.

Delphinium Facts

All parts of the delphinium plant are toxic to humans and livestock if eaten.



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