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MMWD Blog: Think Blue Marin

Welcome to our blog! Written by staff at MMWD, “Think Blue Marin” explores all things water in south and central Marin—water supplies, conservation, new projects, watershed management, and more.

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Dec 31

To Prune or Not to Prune

Posted on December 31, 2014 at 9:10 AM by Ann Vallee

by Charlene Burgi

January is always earmarked for pruning some of our trees, shrubs, and vines. But did you ever wonder why we prune? Or why some plants are pruned harder than others? And why some plants are better pruned in winter than other times of year? In the next few weeks we will unearth some answers.

This time of year always finds me rummaging through my books about pruning. I found it humorous that one pruning book suggested the best way to learn how to prune was to study the mistakes made by your neighbor! While I have seen some gross pruning cuts in my day, the nasty cuts didn't explain why or where to cut, only where not to cut. With that said, let this be the first note: Cutting in the middle of a branch just to shorten the height of a tree is criminal. It is like having a doctor amputate one of your limbs at mid length of a bone. The plant branch is no different. Always cut back to another connecting limb or joint.

Note two: We prune for several reasons. Plants can grow in directions that may not be acceptable in our gardens. For example, bougainvillea is a gorgeous plant that grows lethal thorns. A branch growing into the entryway to our front door would not be welcoming to anyone snagged by the plant’s errant growth. This type of pruning is considered directional pruning.

 narrow V crotch
A tight V-shaped crotch where
two limbs form can cause a tree
to split down the middle.
Other pruning techniques are for the general health of the plant. All dead wood should be removed, as well as the weaker of two branches rubbing against each other. Inspect the plant and remove the weaker or injured branch back to a stronger limb to allow needed light and air into the center of a plant. Check for diseased or injured branches and remove them before they spread the infection to healthy limbs.

General pruning to avoid future problems is yet another reason to grab a pruning tool. A tight V-shaped crotch where two limbs form can cause a tree to split down the middle as the tree ages. Remove the smaller of the two limbs to create a stronger tree. If you are in the market for bareroot trees (and now is the time for shopping for bareroot stock), look for a gentle curve, like a U, where limbs form.

We also prune to control the shape of a plant, to encourage or discourage growth, and to promote healthy flower and fruit production. In the upcoming weeks, we will go into more detail about these types of pruning. Timing is important and will explain why some plants such as quince, forsythia, and lilacs are better pruned after spring than in the middle of winter!

 Two types pruning tools
 Two types of pruning tools
Another major pruning concern is choosing the right tool for each job. A chainsaw works wonders on a large tree limb, but keep it away from roses! Hand pruners are perfect for small twigs, perennials, roses, and berry canes. Hedge shears need to remain in the garage when you’re doing any heavy pruning. Their job is specified in their name … shearing hedges only! Hand saws should be used for small branches, and lopping shears and pole pruners are required to remove limbs less than an inch and cuts that are too high to reach. Jack just reminded me that there are now gas and electric pole chainsaws that allow you to reach up to 10 feet into the tree for removing bigger limbs. Before you begin pruning anything, be certain the chains and blades are well oiled and sharpened.

Stay tuned for more technical details in the weeks to follow. Meanwhile, a very happy and healthy new year to all of you.


Alice Bachelder
January 3, 2015 at 6:36 PM
The Plant Amnesty website is very useful in explaining and picturing the basics of pruning. Perhaps your readers would like to check it out. www

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