In northern gardens coral bells require extra winter protection. Alumroot has a shallow, fibrous root system, which makes it quite susceptible to frost heaving. In late fall it should be covered by a thick layer of mulch (6-12″) – use anything that is insulating and can be easily removed in the spring. Consider leaves, straw, or even snow. Keeping the leaves and crown intact through the winter can also be insulating. In early spring, once the threat of frost has passed and before the new leaves emerge, all dead foliage should be removed to help prevent disease.
As with other perennials, it is important that the plant has been watered going into the winter, before the ground freezes.
Heuchera in mild climates will be true to their ‘evergreen’ label, and provide wonderful winter interest. In spring, old and damaged foliage should be removed as new shoots emerge.