In Japan, apprentices are not allowed to do any pruning, says Peter Lynn, owner of Pomarius Nursery. They only pick up the pruning debris.
"This is how they learn -- by what is removed," he explains. "They aren't allowed to cut the tree until they are masters, in 10 or 15 years."
If you don't have that kind of time, here's the short course on the basics of pruning a Japanese maple, courtesy of Lynn.
WHEN TO PRUNE
Lynn prefers to prune Japanese maples in late summer, but beginners will find it easier to prune when trees are leafless and dormant in late fall to midwinter. Light pruning can be done any season except spring, when sap is rising.
WHAT TO PRUNE
The goal of pruning is to encourage the tree's natural and healthy growth habit. If you don't know your particular tree's habit, do a Google image search to see what it's supposed to look like. Look the tree over carefully, even getting under it and looking up, to identify what you want to prune.
You'll want to get rid of:
• Broken, dead or deformed branches. Winterkill generally shows up on extremities -- branch tips and small twigs. You'll also often find deadwood at the bottom and inside of a tree, where branches have been shaded out.
• Crossing branches. They often rub against each other, removing bark and allowing diseases and insects to enter a tree.
• Branches growing inward or in the wrong direction. These might include branches growing skyward on a tree that has a weeping form.
• Narrow-angled branches, sometimes called narrow crotches. These occur when two branches grow at angles less than 45 degrees from each other. Bark can become trapped in these narrow junctures, making them more prone to breakage. Beginners beware, it's best to consult an arborist for large branches with included bark.
• Branches growing parallel. Thinning these branches creates definition between branches.
PRUNING TOOLS
Use bypass pruners to cut branches as thick as your middle finger and smaller. Use a pruning saw for larger limbs. Make sure blades are sharp.
HOW TO PRUNE
• Work from the bottom up and inside out. Note that Japanese maples have an opposite branch pattern rather than an alternate branch pattern.
• Prune away dead and overlapping branches, as shown in illustration A. Deadwood is relatively easy to spot; dead branches are leafless in the growing season, brittle and a dull gray color, unlike healthy branch color.
• Use what's known as a "selective heading cut" to remove main branches growing between two healthy buds or branches, as shown in illustration B. Cut as close as you can to the base without doing any damage to the buds or other branches.
• Prune side branches back to a healthy wood. Be sure to leave the branch collar, the swelling where a branch joins the trunk, as shown in illustration C. Cutting into the collar or leaving a longer stub will delay or prevent healing.
• Do not cut off tips. It results in rapid, unhealthy growth, as shown in illustration D.
• For larger branches, use the technique shown in illustration E to prevent limbs from breaking during pruning.
OTHER TIPS
• Direct growth by controlling buds. Buds point in the direction they will grow, and one often becomes the dominant branch. You can direct the growth by rubbing a bud out with your fingernail, or you can wait to see how the branches develop.
• Don't seal pruning cuts; this old practice has been shown to be unnecessary and sometimes counterproductive.
• Avoid pruning that results in large differences in branch diameters. Pruning a large branch back to a small side branch gives an unbalanced appearance. Light pruning limits regrowth and protects bark from sun scorch.
• Periodically step back and examine your work from different angles. Look at your tree from the base up, following a branch upward to assess what and where to prune. Don't rush, and if in doubt, don't cut.
• Avoid heavy annual pruning to make a tree that's too big fit into a small garden. Instead, remove it, give it away and replace it with a more size-appropriate tree.
FIND IT
Pomarius Nursery
1920 N.W. 18th Ave.
503-490-6866
DULL TOOLS MAKE POOR CUTS
Jesse Bennett of Sharpening4U, a mobile tool-sharpening business, recommends annual cleaning and sharpening of pruners; twice a year if you use them a lot.
Sharpening4U sharpens blades and takes pruners apart to clean, lubricate and adjust so they function like new. Fees are based on blade length, beginning at $2 for small pruners. Look for them at area farmers markets, or for jobs over $20, they will come to you.
Contact: 503-962-0574 or sharpening4u@yahoo.com
-- Freelance writer and master gardener Lisa Albert; lja.garden@verizon.net