Delphinium in November: monthly care

Delphiniums benefit from two distinct pruning sessions each year: one in early spring and one after flowering. In March, as new growth begins, cut back any old, dead stems left from the previous year to ground level. This tidies the plant and reduces the risk of slug damage to emerging shoots. At the same time, thin out the young shoots when they reach about 10–15 cm tall, leaving only four to six of the strongest per clump. This may seem drastic, but it channels the plant's energy into fewer, sturdier stems that produce larger, more impressive flower spikes and are less prone to wind damage. After the main flush of flowers fades in mid to late summer, cut the spent flower spikes back to a healthy side shoot or to just above a set of leaves lower down the stem. This often encourages a second, smaller flush of blooms in late summer or early autumn. Once this secondary flowering finishes, or by November at the latest, cut all stems down to ground level. Remove and compost or bin the foliage to minimise overwintering of pests and diseases, particularly slugs and mildew spores. Use clean, sharp secateurs or loppers for all cuts. Delphinium stems are hollow and can collect water if cut at an angle, so a straight cut just above the crown is best. Wear gloves when handling delphiniums, as all parts of the plant are toxic if ingested and the sap can irritate skin.