Plants left in the ground

A generous layer of mulch will insulate roots and tubers

NOT all tender plants growing in borders need to be lifted for winter – indeed, you may not be able to do so if they have grown too large.

Evergreen agapanthus, which are generally less hardy than deciduous varieties, can be protected in borders with a thick mulch of straw, chippings, well rotted organic matter or Strulch (an enriching, straw-based mulch) over their root area.

Dahlias and cannas are left in the soil until their leaves are blackened by the first frosts. If your garden is very sheltered you can leave dahlias in the soil through winter. Generously mulch over the tuber and root area and cut back their top growth to 4in (10cm).

Penstemons are another plant that can fall foul of really hard winters, but they are usually hardy enough to be left in place with their top growth reduced by a third so this year’s stems will protect the plant’s more vulnerable crown.