There has never been a better time to try delphiniums and if you sow them now, grow them on in pots and overwinter them in a cold frame or sheltered spot you’ll have sturdy, young plants that will quickly grow away to flower in summer. They great thing is that there are delphinium varieties to fit in all kinds of spaces, from the smaller, open-flowered Belladonna types to the stouter tightly-bloomed spires of the Centurion series and the traditional Pacific hybrids. Modern breeding has improved the stature of the plant, with stronger more compact stems being better able to stand on their own without staking, producing stronger, cleaner colours in a range of petal formations from single to completely double, with prominent ‘bees’ in the centre adding to the allure. If the main spike is removed once the blooms are over side shoots will form to continue the display.
The Belladonna types are useful for more informal cottage gardens, ideal for massing among other perennials and annuals or even pots. The Delphina types have greater stature, but are very compact, ideal for smaller borders, while taller varieties are more effective if given space to develop in herbaceous or mixed borders. Taller varieties do better in moist, but well-drained rich soil with plenty of organic matter to generate strong, vigorous growth to get the stature they need. All thrive in sun or semi-shade, but need more moisture the hotter it is. They struggle on dry, impoverished soil, producing weak growth and a disappointing display of bloom. Feed them with a general-purpose fertiliser and liquid feed with a high potash fertiliser when the flower spikes form and give them a water and keep them mulched if the weather turns dry. The main scourge of delphinium is of course slugs and snails which love to devour fresh young growths in spring, so try your best to get them through this period so they grow away from danger and you’re all set for a display to remember!