Culture
Grow in fertile, medium moisture, well-drained soil in full sun. Easily grown from seed. Needs protection from wind. Fertilize regularly. Remove spent flower spikes after bloom to encourage continued bloom and/or a possible second, albeit smaller, autumn bloom. A short-lived perennial that is often grown as a biennial or annual. Dislikes the heat and humidity of the deep South, but has better heat tolerance than many of the delphinium hybrids. Appreciates some afternoon shade.
Noteworthy Characteristics
Delphinium grandiflorum commonly called Chinese larkspur, is a loose, free-branching plant which typically grows 1-2' (infrequently to 3') tall and features loose racemes of gentian-blue (occasionally white) flowers. Individual flowers are complex and asymmetrical and feature five sepals, one of which is spurred into a distinctive prong resulting in the common name of larkspur. Palmately divided green foliage.
Genus name comes from the Greek word delphis meaning dolphin in reference to the flower bud shape of some species purportedly resembling a dolphin.
specific epithet means large-flowered.
Problems
Powdery mildew, botrytis blight, fungal blights, leaf spots and crown rot can be problems. Slugs and snails can be particularly destructive problems. A regular insecticide and fungicide treatment regimen may be appropriate.
Uses
Provides color and contrast to the perennial border. Effective in small groups or as a massed planting.