They are good cut flowers and will last about 6 to 8 days in a vase. Immediately after flowering, cut off the old flower stalk to encourage additional flowering in late summer or early fall. The flower spikes produced during the second flower display won't be as large or as full as the first bloom. The Chinese delphinium is a summer-blooming species. It blooms throughout the summer if the plants are cut back regularly.
Larkspur spikes can easily be air-dried.
Harvest spikes when about four-fifths of the florets on the spikes are open. Remove the foliage and hang small bunches of spikes upside down in a dark, well-ventilated area. When the flowers feel papery, they should be stood upright to finish drying. While delphiniums are spectacular plants, many are short-lived perennials. Most last only 2 or 3 years in the garden.