Usually us gardeners recommend leaving old stems and seedheads on for the birds to find, and the frosts to silver the skeletons. I would love to be putting up pictures of grass seedheads shining with hoar frost. However this December in the south of England,we have had dull dark damp days with little sun and most dying stems are rotting as they fall. This season we really must get out and clear the old fallen foliage out of the way. In this mild climate, air flow is essential for plant health, even the gales can’t blow out the botrytus if the resting surface level buds are covered in last seasons rotting stems. I find a heavy craft knife the most useful to slice through the stems, quicker than secateurs, then the other hand can drag the stems away. My trusty Showa 370 gloves are enough protection usually to stop snagging my fingers on sharp stems.
The early flowering plants are already moving you should be able to see the flower stems coming through of Epimediums and Hellebores and some daffodils and snowdrops are already in full growth. This year there should be a long list of plants flowering on Christmas Day, write them down and send them in.