There is plenty to do in the garden in January if the weather permits. Many woody perennials that bloomed in fall or winter and have grown leggy and may be flopping over can be cut back to new basal growth when it starts to appear. This includes Russian sage, asters, Tagetes lemmonii (perennial marigold) anemones and mums. This is also the best time to cut back buddleias. Cut them back almost to the ground as long as the stems show some new basal growth to keep them a manageable size in the garden. A layer of mulch will help keep the ground warm to promote good root growth this time of year as well as help retain any moisture that the rains bring.
There is no harm in planting perennials this time of year as long as the ground is not too wet. Digging in soggy soil will only result in large clumps when the soil starts to dry out and it may be difficult to get the soil to properly fill in around the plant roots. Air pockets around plant roots will kill the exposed roots and may even kill the plant if there are too many gaps underground. Walking on wet soil also leads to compaction.
One of the advantages of living and gardening in Southern California is having year round color. Now is a good time to take note of areas that could use some interest this time of year and look for plants that are in bloom this month. A trip to the nursery or even driving around the neighborhood to see what is doing well in other people’s yards this time of year should be a good inspiration. If it is too cold or wet to plant this month, take notes to remember to put in winter plants this spring for next year’s interest. The damp weather can cause some fungal problems in the garden this time of year. Keeping spent blossoms off the ground under camellias will prevent petal blight. Keeping the ground clean of dying plant material is the best defense against any kind of fugal diseases.