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January is pruning time in the Northern Hemisphere. Even in places where it’s not snowy — like Sacramento, my hometown — it’s time to get those trees and vines in shape for a fruitful summer.
The master gardeners from our local University of California Cooperative Extension gathered at the Fair Oaks Horticultural center recently to demonstrate to a packed house the basics of pruning fruit trees, berry and grape vines, and roses.
Among them, these masters have hundreds of years of experience in every area of gardening. I hope you’re making good use of the master gardeners in your area. They’re such a fabulous (and free) resource.
Pruning fruit trees
Is there an overgrown fruit tree lurking in your yard?
If you like its fruit and it’s not diseased, some strategic pruning could rejuvenate the tree and promote a healthy crop.
Chuck Ingels, farm advisor from the UC Cooperative Extension in Sacramento County, shared three methods for pruning an overgrown fruit tree:
Method 1: Maintain the height of the tree, but thin out the branches.
Remove any dead or damaged limbs, and any branches that grow toward the interior of the tree or rub against other branches.
Thin out the canopy to allow sunlight and air circulation. Keep the tree at a height you are able to pick the fruit.
Method 2: Reduce the height slowly over three years.
Get oversize trees back to a manageable height (to where you can reach fruit) over a 3-year period. Decide how tall you’d like the tree to be, and trim off one-third of that height each year. To reduce the chances that the pruning wounds will become infected, make major cuts in April (or early spring) when there is less rain and leaves begin to shade the cut.
Pruning could expose large branches to sun, so paint those with a 50-50 mixture of white latex paint and water to prevent sunburn and boring insects. Remove new sprouts that appear near cuts throughout the season. Thin out the canopy as needed to allow in sunlight and circulation.
Method 3: Drastically cut back all main branches but one.
For some trees that are capable of resprouting from large lower branches, such as apples, pears, citrus and avocado, you may elect to prune back a too-tall tree in one season.
If the tree has major branches below 6 to 8 feet from the ground from which new sprouts may grow, the tree may be a candidate for this method. (Note that trees with thick bark may not resprout; for those use Methods 1 or 2.)
Cut back the main branches to approximately 2 to 6 feet long to create the desired size. Be careful not to tear the bark as you remove large limbs. (See Publication 8058 on Pruning Overgrown Fruit Trees for more information.)
The best time to do this major pruning is early April when new growth is beginning. Because you’re removing so many limbs, be sure to leave at least one leafy branch to provide photosynthesis and nourishment. This branch may be pruned away in future years if desired.
Prevent sunburn by painting exposed branches with whitewash or 50-50 mixture of white latex paint and water.
Learn more about all three pruning methods in UC ANR Publication 8058.
Train young fruit trees
Ideally, fruit trees will be shaped from the start to the ideal size and shape. Whether your tree is dwarf, semi-dwarf or full-sized, a few basic principles can help you create a strong, accessible fruit tree.
1. Prune to create an open center.
Many stone fruit and nut trees are commonly pruned to open up the center of the tree to make it easier to reach the fruit and to allow sunlight to reach all the branches.
After planting a bare-root tree, lop off the main leader to about 18 inches. This will encourage new lateral shoots to form.
During the first growing season, select three or four shoots to become the main scaffolding. Space these apart vertically and around the trunk, beginning about 18 to 24 inches above the ground. Trim back to no more than 2-½ feet in late May or early June to encourage secondary branches to form.
In the first dormant season, continue to shape the tree. Prune out limbs growing directly above another branch, or those that grow completely horizontal or downward, as well as those growing straight up. Choose limbs growing at about a 45 degree angle upward, distributed well around the tree. Maintain an open center and an upward, outward growth pattern.
For mature trees, maintain an open center by pruning away shoots growing toward the center or crossing other limbs. Retain branches that fruited the last one or two seasons, removing older branches.
2. Train a central leader
Some trees tend to have a dominant central leader. For this pruning method, shape branches into tiers of about four branches each.
You may need to stake each tier of branches to grow into an upward and outward direction. Offset the branches on each tier as they sprout.
See a chart of recommended pruning methods for several types of fruit trees, along with modifications of these primary pruning methods, in ANR Publication 8057.
Pruning berry vines
There’s nothing like bringing in a fresh colander of berries for breakfast on a summer morning. Cane berries — blackberries, boysenberries, raspberries — may grow well in your area.
Most of these cane berries need to grow on a trellis, which keeps the berries up off the ground and makes them easier to harvest.
Between strong (4 to 6 inch) posts, string three levels of galvanized wire to a total height of about 6 feet.
After the harvest, prune back to the ground the canes that fruited, leaving new shoots to become next year’s fruiting canes. Cut back new canes to 5 or 6 feet, and spread out along the trellis in a fan shape.
Raspberry roots will escape their borders, so cut out the escapees in early spring.