December in the English garden is usually relatively restful, so take advantage. Cut back your borders. After a few hard frosts at the end of November and in early December, all the plants in the herbaceous and mixed borders will now have finally died back. Now its time to cut them back - remember to leave 10cm of plant showing. This helps in the Spring to show where plants should be coming through and identify any winter losses. Deal with Dahlias. Dahlias will have truly blackened now, so cut them down. Some people like to lift...