Delphinium elatum or larkspur is a perennial in the buttercup family producing tall, elegant spires, densely packed with early summer blooms in purple, blue, pink or white. It can be used as a border plant to add extra height. They prefer a well-drained, sunny position and thrive when fertilized no later than August. Remove the first flower shoots as they fade to encourage new shoots. In windy areas, use stakes to secure the plant as it can reach up to six feet. Regular watering is required.