Delphinium elatum ‘Guardian Blue’

If you want that quintessential delphinium blue, ‘Guardian Blue’ delivers. Part of the F1 Guardian series, it produces tall, dense spires of rich blue florets, each with a small white eye, on notably strong stems.

Expect around 90cm to 1m in height, ideal for the back of a sunny border. Plant in full sun in fertile, moist but well-drained soil. The Guardian stems are sturdy, but a cane on an exposed spot is cheap insurance against summer wind.

Cut back the spent spikes after flowering for a chance of a second flush. Keep an eye out for slugs on the spring shoots. Few plants give a border that vertical drama quite like a blue delphinium.