Continue leaf removal. If leaves stay on the grass for a few weeks and get thick enough to totally block out the light, they will surely kill the grass.
Try to keep any tender plants from freezing by wrapping them with burlap or any material to keep the wind from blowing on them. If possible, put something on top of perennials and bulbs and such for insulation.
Use leftover Christmas trees & wreaths as mulch, just cut off the branches & lay over beds.
Winter mulch in beds & around trees should be replenished to 2” - 3” deep.
Dormant oils should be applied on trunks & branches of trees to kill over-wintering adult insects & their eggs. The oil will coat certain insects and smother them.
Prune your woody plants including trees and summer-blooming shrubs & vines.
Prune out weak & diseased branches and only select the strongest branches to remain.
Let’s think about our birds and keep out some food & fresh water and If the ground is not frozen or too wet.
January is also a great month to start thinking about new plants for your landscape design as March is the time to start any transplanting, removals and additions.