Columbine

Columbine is completely hardy and survives a Central European lowland winter in the bed without protection. In autumn, after the foliage has died back, cut the stems back to a hand's height, or leave them standing and shorten them only in spring before new growth; only container-grown and newly planted specimens do you cover as a precaution with brushwood or leaves, and make sure the soil is free of waterlogging.

The easiest way to propagate columbine is by sowing. The plant often does this itself: from late summer the dry seed capsules open and scatter the seeds across the bed. This self-seeding leads to new, often surprising colour combinations, because columbines cross freely. For deliberate sowing, collect ripe capsules before they burst. Columbine is a cold-stratification and light-germinating seed: with spring sowing, a cold period helps. To do this, store the seeds cool in the fridge for a few weeks, then sow from March to May. As light germinators, only press the seeds in; do not cover them with soil. At around 18 to 20 °C they usually germinate in 2 to 6 weeks. The easiest way is to sow freshly harvested seed directly in late summer. They then get their cold period over winter outdoors. Division is possible but demanding: columbine forms a deep taproot that tears easily when divided, which is why some people advise against it altogether. It is most likely to succeed with older, large clumps (from about 3 to 4 years) on a cool, overcast day in spring before growth starts or in late summer after flowering. Dig up the root ball completely, divide it at natural dividing points with several strong shoots per section and replant immediately. Columbine is short-lived (about 3 to 5 years); regular self-seeding secures your stock in the garden in the long term.