Tall and majestic, delphiniums are the giants of the perennial border. Their densely covered flower spikes not only provide an eye-catching show of mid-summer colour. Delphiniums thrive in a sunny location with rich, well-drained soil and should be staked to support the heavy blossoms. To encourage germination and break dormancy, chill seed in the freezer for 24 hours prior to sowing.