Delphinium grandiflorum was bred to solve one of the genus's most persistent problems: its hatred of summer heat. Native to Siberia and northern Asia, and developed into cultivars like the well-known 'Blue Butterfly', this dwarf larkspur tops out at around 15 inches — a scale that invites use in containers and as a mid-border filler rather than the back-of-border vertical drama of its taller relatives. The flowers are a deep ultramarine blue, plentiful, and carried on branching stems through spring.

Treating it as an annual or biennial sidesteps the short-lived perennial problem that bedevils most delphiniums — it typically lives three years at most, so planning for replacement from the start avoids disappointment. Deadhead consistently for a second bloom, fertilize regularly to sustain the flowering, and provide afternoon shade in warmer zones. Cut back in late fall. In a container composition it reads as the 'filler' in the classic spiller-thriller-filler model, dense and floriferous enough to hold its own at close range.