In winter there is very little to do in the research beds. I tidy up the worst of the weeds in autum and then mulch with fallen leaves at the end of November.
Then I leave it all alone. No cutting back of old stems, no digging, and no further tidying of any kind. I dont even turn the compost heeps.
This inactivity is important as all that dead stuff is where the bugs will be during the winter. Birds will enjoy the seed heads. Worms will be working under the blanked of leaves and slowly breaking them down and taking them into the soil. Beetles and will be pupating under them too. Butterflies, moths and even spiders may be hibernating amongst the stems. You may even have bumblebees and solitary bees nesting just under the surface of the soil or in you compost.
So, I leave it all alone for as long as possible. But eventually I want to give light and encouragement to my perenials which will be the important pollinator food when they flower. Late April or early May is when I usually finally clear it all away and do a big weed. Even then, I weed with a hoe and never dig more than a few inches down.