Delphinium

Delphinium is hardy and survives a Central European winter outdoors without protection. Cut the stems back close to the ground in late autumn; only in bare, wind-exposed spots can you lay some leaves or brushwood over it.

Sowing: Delphinium is a light-germinating plant. The seeds need brightness to germinate. Cold treatment helps: one to two weeks before sowing, put the seeds in a damp cloth and place them in the fridge. Then sow in spring in seed compost and press the seeds in only very lightly, never covering them with soil. Keep them cool and bright; at around 13 to 15 °C they usually germinate within two weeks. Important: when grown from seed, elatum hybrids often do not reliably pass on the traits of the cultivar. For true-to-type offspring, prefer cuttings or division.

Basal cuttings (for true-to-type plants): This is the most reliable method if you want to keep a particular cultivar. Spring is the right time, as soon as the shoots at ground level are 8 to 10 cm long, typically March to April. Remove some soil around the clump and cut a shoot out close to the root collar, ideally with a small piece of root. Take only firm, non-hollow shoots, because hollow stems easily rot while rooting. Insert the cutting in free-draining substrate (e.g. a soil and sand mix), keep it evenly moist and place it somewhere bright but out of direct sun. After four to six weeks it has rooted and can go into the bed.

Division: Every three to four years in early spring, as soon as the first shoots appear, division is worthwhile: the clump is rejuvenated and flowers more strongly. Dig the plant up generously, take care with the fleshy and somewhat brittle roots, and divide the clump with a sharp spade or knife. Each piece needs at least two to three shoots and intact roots. Replant the pieces straight away and water them in well.