Q: Do I need to prune my fruit trees in the winter? — Doris, Morro Bay
A: Winter pruning of deciduous fruit and nut trees ensures tree health and optimal crop production.
Winter is the optimal pruning time for a couple of reasons. Without their leaves, the branching structure of a tree and any diseased or damaged limbs are readily apparent. Also, deciduous trees’ excess food (i.e., carbohydrates) is stored in their roots, so pruning during dormancy doesn’t decrease available food stores for the trees when spring arrives. The carbohydrates will be present to push spring leaf growth.
There are some important exceptions to winter pruning.
Apricot trees should be pruned in August or September before winter rains to prevent Eutypa fungus infections in the pruning cuts. If evergreen trees such as avocado and citrus need pruning, it is best done in early spring after any danger of frost and before a fresh spring growth cycle. Finally, if it is raining or there is rain in the forecast, do not prune your trees. Pruning cuts will heal faster in dry weather, helping to keep trees protected from bacterial or fungal infections.
There are several training methods.
One is to prune around a central leader, where the main trunk (or leader) is allowed to grow and support several scaffolding branches. This can lead to very tall trees, so more often trees are pruned with a modified central leader. This is done by removing the leader just past a lateral branch to limit the tree’s height.
Another method is known as the open center or vase, where the center is kept free of large branches.
If space is limited, gardeners may wish to espalier their fruit trees. Espaliered trees are grown flat against a wall or fence. Apples, pears and Asian pears are especially suitable because they develop multiple spurs without many upright shoots.
If you wish to learn more about winter pruning of your fruit and nut trees, please at tend the Advice to Grow By workshop at the Garden of the Seven Sisters on Saturday. The presentation will begin promptly at 10 a.m. in the downstairs conference room. If weather permits, there will be an outdoor pruning demonstration in the garden.
GOT A GARDENING QUESTION?
Contact the University of California Cooperative Extension Master Gardeners: at 781-5939 from 1 to 5 p.m. on Monday and Thursday; at 473-7190 from 10 a.m. to noon on Wednesday in Arroyo Grande; and at 434-4105 from 9 a.m. to noon on Wednesday in Templeton. Visit the UCCE Master Gardeners web site at http://ucanr.org/sites/mgslo or email firstname.lastname@example.org .