The towering spires of delphinium are often compared with church steeples, yet it is the long nectary of the flowers that provides the inspiration for the name: The dolphin’s nose, Greek delphis, gives us delphinium, and the feet of larks inspired the nickname larkspur. Lovelier still to the tongue is the Spanish nickname espuela del caballero—the cavalier’s spur.
While delphiniums are beautiful in their own right, their qualities are appreciated all the more because they often require a lot of care. The gardener who anticipates the challenges in advance will have a better chance of success.
Seed catalogs reveal a multitude of color choices, including stunning and varied shades of blue, pastel pinks and lavender, spritely yellows, whites, and two-tone varieties. Plants started in February will bloom the same year.
The sunny days and cool nights of coastal New England, plus its ample rainfall, present optimum growing conditions, as does the western United States. In fact, in the cooler zones delphiniums can be expected to survive for a number of years, whereas in warmer regions a plant may last only a season or two. The species forms of delphinium seem to be longer-lived than the hybrids.
In addition to living in the right place, the delphinium grower needs to be diligent about modifying the immediate conditions. While moisture is essential, wet soil will cause crown rot. Delphinium plants should be set in rich, well-drained soil. The bed should be prepared deeply, enriched with compost, and sweetened with lime, bone meal, or wood ashes. Plants emerging from self-sowing of the previous year should be thinned so that there is adequate ventilation between them. Fertilize regularly or top-dress with rich compost or composted manure.
Because the spectacular flowers are so top-heavy, solid staking is essential. Wooden stakes may be stained green to be less conspicuous. Thin bamboo stakes (often available in green) should be pushed deeply into the ground. Stake each stem separately to keep the blooms erect. If your landscape is informal, you might also consider using large twigs or small branches for staking.