These were originally bred in California as annuals and developed for their tall spikes as well as the semi-double and double flowers; they are based largely on d. elatum.
Updated by: Niels Klazenga, December 2017
Delphinium 'Black Knight'
Flowers dark violet with black patch.
Delphinium 'Blue Bird'
Flowers blue with a white patch.
Flowers lavender with pink tint and a white patch.
Delphinium 'King Arthur'
Flowers violet with a white centre.