The garden in January
In case of a sudden cold spell check winter protection, especially if no thick snow cover is protecting the plants.
Evergreen shrubs evaporate water also in Winter und must be watered from time to time (when ground is frost-free) during longer dry spells.
Winter pruning: trees and shrubs are pruned during the dormancy period; fruit trees and berries are thinned.
Earthwork for garden construction and remodelling can be done all winter long when the ground is frost-free and weather permitting.
Roses need fertilizer at the beginning of the growing season - end of February to April, depending on weather and climate.