Four things to keep in mind when growing your own delphiniums
As an English cottage garden staple, delphiniums prefer moist, cool summers. Their stems are hollow, so they fall over if it’s too windy. Even if you don’t live in a breezy area, consider staking each plant as the dozens of ruffled, trumpet-like flowers on the tall stalks can get quite heavy. Plant in full sun and, rather than clump them together, give them plenty of breathing space. If you live where summers are hot, consider planting larkspur. It’s very similar to delphinium, but is an annual. Larkspur also comes in orange, red, yellow and maroon.
Plant in fertile soil with good drainage. Before planting, add plenty of compost and after planting cover soil with mulch to keep in the moisture. Water regularly.
Delphiniums are short-lived perennials. In their first spring, they send up spikes with several shoots. Thin back to one or two shoots per stalk, then three or four shoots in their second year and five to eight shoots in their fourth year, when they reach their peak. They bloom all summer long and you can keep them blooming longer by deadheading spent flower spikes back to small flowering side shoots and, when blooming has finished, cut stalks to the ground. New, smaller flower stalks will develop that will survive light autumn frosts.
4. Where to plant
As delphiniums grow more than a metre tall, they are ideal for gardens where space is limited as the flowers grow up rather than out. Or plant them at the back of a wide garden bed, with smaller plants in front. Just make sure they are in full sun. Protect them from the wind by surrounding with other cottage garden plants such as hydrangea and spiraea.
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