Electric blue
IF the rose is the queen of the English cottage garden, the delphinium is the king. In June and July, its tall flower towers dazzle at the back of the border in every shade of blue, from pale Wedgwood to deep-sea cobalt. Mature plants can reach 6ft (1.8m) high, producing over 100 blooms on each of its spikes, which point to the sky like the spires of tiny blue cathedrals.
These border stars are the perennial Elatum delphiniums, which can be planted now in spring. They are best bought from specialist suppliers to ensure quality, and because many perennial delphiniums available in garden centres are the Pacific Hybrids that have declined in quality since their introduction almost a century ago.
