Don’t cut down herbaceous perennials
It’s tempting to cut down faded herbaceous perennials and add them to the compost heap but if you leave them as they are, they will provide hibernation places for insects and winter interest. Penstemons are best left (except for deadheading) until the spring. In mild areas, they can carry on flowering into early winter. The old faded stems will help to protect the crowns from cold. Mulching over the crowns in colder areas will also help.
Hellebores rarely flower naturally by Christmas, despite their common name of Christmas rose. They can be encouraged to flower a little earlier, if you want, by covering them with cloches, potting them up and bringing them into a warm greenhouse, or placing them on a windowsill inside the house.
Save alpines from rot
Protect alpines from the wet, if you have not done so already.
Transplant young trees and shrubs
This is also a good time to transplant trees and shrubs growing in unsuitable positions. However, if they are more than a couple of years old, you are unlikely to be able to remove an intact enough rootball to ensure the plant’s survival in its new position, and you may be best advised to leave well alone.
Don’t transport pests and diseases
When bringing plants indoors, check them for pests and diseases. Poor-looking plants can always be tipped out of the pot to check their rootballs for signs of over or under watering, or for soil pests like vine weevil larvae.