Your Garden … with Kate Russell: Now is the time to prune your trees, but learn before picking up shears
Published in the Dec. 21, 2016 – January 3, 2017 issue of Morgan Hill Life
By Kate Russell
Pruning fruit and nut trees in winter is one of the best ways to share with your South Valley friends and neighbors more delicious crops next summer. With fall over, it’s also a lot easier to prune without all those leaves blocking your view.
Winter pruning lets you improve the structure, size, and overall health of your fruit and nut trees. The only exceptions are cherry and apricot. Those trees are susceptible to a fungal disease called Eutypa dieback and should be pruned in August.
Before you start pruning, it’s a good idea to learn as much as you can about your trees. Different trees have different needs in Gilroy than in, say, Minneapolis. Also, each species has its own needs. Some trees produce fruit on new growth, while others produce fruit on second year growth.
Most fruit trees should be pruned by 15 to 20 percent, while peach trees should be pruned 50 percent. Learning the details about your particular trees can make a big difference in how and where you make pruning cuts. Before you make those cuts, you’ll need the proper tools and safety gear.
Putting on long sleeves, boots, gloves, and eye protection before pruning for safety is always an excellent idea. One little piece of flying bark can feel like a jagged boulder in your eye. It’s not worth it. Also, make sure your tools are clean and sharp. It is easy to sharpen your tools with a file. You can see how at the Santa Clara County Master Gardeners YouTube website.
There are two basic types of pruning tools: bypass and anvil. Anvil cutters have one sharp blade and one flat blade, which can crush plants rather than make clean cuts, so they should be avoided. You will need hand pruners, loppers, and a curved pruning saw. Also, have a 10 percent bleach solution (1 part bleach, 9 parts water) or disinfectant bathroom cleaner handy. You will use this to sterilize your tools between each plant and after cutting off any diseased plant material.
Regardless of the species, diseased, damaged, and crossed limbs should be removed first. Next, prune for size and structure in ways that allow for good sun exposure and air circulation. Keep in mind that vertical branches tend to be more vegetative (leaf producing), while horizontal branches produce more fruit, and your tree needs both. You will use two types of cuts when pruning: thinning and heading. Heading cuts shorten branches, stimulating new growth where you want it. Thinning cuts are the removal of unwanted branches. When making thinning cuts, avoid damaging the branch collar without leaving nubs. Branch collars are areas of raised bark where a limb emerges. These living cells help a tree to heal itself.
These pruning tips can help you get the most out of your efforts (and your trees):
• Make cuts ¼-inch above nodes that are facing the way out want new growth to go.
• Prune for a size that will be easy to maintain and pick fruit.
• Aim to distribute sunlight evenly throughout tree.
• Most of the pruning should be done at the top of the tree, to allow more sunlight to reach the lower branches.
• Remember that one big cut can prevent several smaller cuts.
• Keep in mind how the tree will grow over the next few years.
• For heavy producers, remove excess fruitwood to prevent broken limbs.
• Sealants are not needed. Trees know how to seal themselves.
• Be sure to pick up and dispose of any rotting fruit or mummies.
As you prune, take the time to step back and look at the tree from several angles to make sure you are getting the shape you want. While you’re at it, January is the best time to prune roses in the Morgan Hill area. Keep three to six strong, healthy canes per plant, leaving three to five buds on each cane. Make diagonal cuts ¼-inch above an outward-facing bud. To learn more, the San Jose Heritage Rose Garden offers free hands-on rose pruning classes in January and February (www.heritageroses.us/PruningLessons.htm).
Kate Russell is UCCE Master Gardener. She wrote this column for Morgan Hill Life.