A favorite of gardeners because of its hardiness and the quality of its blooms, Delphinium has graced small and large spaces for decades. It comes in many varieties, from dwarf cultivars that grow only a few feet tall to massive, cascading plants that approach the height of a man. Both perennial and annual varieties exist, although warmer climates may have trouble sustaining the plant year after year.
They make good background plants in mixed borders and can be massed where height is needed. Flowers bloom in spring and early summer in warm zones and mid to late summer in cooler places.
Delphinium produces exceptional cut flowers. They should be cut when the lowest flowers are fully open on the branch and the top buds are starting to show color. The plants prefer full sun but can flourish in mildly shady environments. Soil should be well composted and well drained. Because they can grow so tall, Delphinium may require staking to support the heavy blooms.
Seeds can be started in pots or trays and sown at 12 to15 inch intervals. Water regularly and thoroughly to encourage strong growth while the plant establishes itself. Once plants are 6 to 8 inches high, apply compost or other fertilizer to encourage the formation of flower buds.
All parts of the plant contain an alkaloid delphinidin and are very poisonous, causing vomiting when eaten, and death in larger amounts. Use care when planting in an area where children might be exposed to the plant.