December’s rains ended Marin’s drought and gave our gardens the deep water soaking our roses and other thirsty plants needed.
Now we must prepare our roses for what I hope will be a beautiful and bountiful blooming season.
Winter in the garden is the time to get to the “bare bones,” the structure and form of our plants. While the roses are not showing off for us now, they are showing us their primary structure. This is evident from their loss of leaves caused by the rains and cold temperatures.
If your roses have not lost all their leaves, they won’t go into dormancy. We encourage forcing roses into dormancy in Northern California in order to get better, stronger and bigger spring blooms. We create this in two ways. First, we encourage leaf loss by spraying the roses with dormant oil spray. I use neem oil on the leaves and on the ground. There are other copper sulfate sprays as well which will discourage rusts and molds from surviving winter and continue thriving for the spring bloom.
You don’t want your spring buds having old diseases. Cleaning up the leaves from the ground around the roses is a MUST to ensure that diseases will not live through the winter. Usually I do two sprayings of dormant oil spray, one after Thanksgiving and a second three to four weeks later. I have on occasion done a third spraying in late January to discourage early bloom growth.
The second step to encouraging dormancy is to do a major pruning. Once all the leaves are gone, you can clearly see the number and direction of major branches growing out from the root ball at the base of the rose. As you observe each rose, consider which branches are bright green and thick and which are looking knobby and woody. The woodier the branch, the harder it will be for nutrients to circulate inside them to feed the leaves at the top of the branch.
Next, consider the shape of the branches. Roses need air and light to reach all the plant. Thus, we suggest the form of the open bowl for hybrid teas, shrubs and grandiflora roses. Climbing roses are encouraged to grow laterally so that they can grow out and up. Now is not the time to prune any Old Garden roses. These are usually one-time bloomers and get pruned after they bloom in May.
Depending on the age of your plant you will want to prune down to three, five, or if older, more viable green stems. You want these stems to grow straight and in an outward direction away from the center of the root ball. Always clean out first any branches that are crossing in front of another and those which grow inward. Remove any fragments or entire canes that appear to be dead. Such die-back occurs occasionally but must be removed at this time.
After identifying the major canes you want to keep in order to maintain the healthy open shape, you can remove the other canes with your loppers or small saw at the base of the root ball. Now look at the remaining canes and look for a sign of a bud growing on the outside of the cane away from the center of the root ball.
You want this bud to be somewhere around the height of your knees. Some people say to prune these canes anywhere from 6 to 18 inches above the root ball and you can do so. I prefer knee high because that is where I can get to. Using the wider blade of your tool under the inside of the cane but above that outside bud you selected, cut off the upper part of this cane at a 45-degree angle. Repeat this as you go around the remaining canes of your rose.
January is always a good time to sharpen your pruners, loppers and saws. It’s also a good idea to use a disinfectant wipe to clean your blades after you prune each rose. This way you won’t be transferring diseases from one rose to another. The recent rains gave growth to many weeds that you want to remove now. Remember to discard your rose debris in your garbage cans. Roses are not good for your compost pile. Be up to date on your tetanus shots, wear protective clothing and good gloves as you head into your garden and have fun! Your efforts now will be well rewarded this spring.
By Vivien Bronshvag, Consulting Rosarian
Edited for the MRS website by Nanette Londeree, December 2019