Photo: BerndH (wikipedia)
The lovely larkspur used to be considered a member of the Delphinium genus and indeed the flowers are similar and the blooms of both may be blue, purple, pink or white. However, larkspurs belong to the Consolida genus, and they have finely divided feathery leaves and poisonous seeds. In fact they are deadly to livestock.
These plants like full sun and rich well-drained soil. Most of the larkspurs we grow in our gardens are annuals, but they readily self seed so they can become almost permanent residents of our gardens.
Modern larkspurs were derived from Consolida ajacis, and some are hybrids resulting from a cross with Consolida orientalis. Just buy a packet of larkspur seeds and sow them in early spring. If the bed is not mulched with commercially made mulch that contains germination deterrent, they will readily self sow in subsequent years.
Consolida is the botanical name because these plants were used in the Middle Ages to help consolidate (i.e., clot) blood. Native to Europe, larkspur is now often found in the wild in North America. It has frequently been used medicinally as an agent for the destruction of human parasites such as lice and mites. When it flowers in May through September, the delicate color and spurred flowers are exquisite to behold, both in the garden and in a vase.