Sumo Gardener

Common Pruning Mistakes | What to Look Out For and Avoid

There are 46% fewer trees on the planet than there were 12,000 years ago. Deforestation is at an all-time high. As an individual, we can all help the earth by looking after the trees in our own backyard and planting new ones, even if they are in pots.

It is important to prune your trees regularly so that they stay healthy and grow to their optimum height, making the most of the sunlight. Some of the common pruning mistakes that you may find includes them leaking sap or not continuing to grow after they have been cut. 


Common Pruning Mistakes to Look Out For

Common Pruning Mistakes to Look Out For

You can rectify these pruning problems with special treatment, and also making sure that you prune your trees at the right time of the year. 

Bacterial Wetwood and Slime Flux

When you have been too heavy in pruning a tree, or damaged the bark, you may find that the tree looks like it is leaking. When a tree is leaking water, this is actually sap that is produced to help protect the tree from fungal infections and bacteria.

There are, however, other tree conditions which lead to a tree looking like it is leaking water - these include slime flux and bacterial wetwood, both of which are reasonably common. If the sap coming out of the tree smells sour and unpleasant, this is a sign of wetwood.

The sap will attract a variety of insects, which can cause damage to the bark of the tree. Slime flux can be treated using a mixture of bleach and water at a 1:10 ratio. This should be applied to the tree weekly for at least a month. There is no treatment for bacterial wetwood. 

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Pruning Branch Tips

pruning problems

Although one of the reasons to prune a tree is to cut it back or restrict its growth, ultimately, pruning a tree will stimulate it to grow new branches. By just pruning the tips of the branches, you will find that 4-6 new branches will grow.

But if you don’t want the tree to become unruly very quickly, you should make fewer, larger cuts instead. The best solution is to prune your tree at the start of fall, when growth slows down.

Look for the more dominant branches - the ones where you are happy with the direction of growth. You should then remove all the competing branches around these dominant branches. Ultimately it will help the tree to stay healthy. 

Over-Pruning Your Tree

One of the most common issues in pruning is that people prune too many branches off

One of the most common issues in pruning is that people prune too many branches off, especially if the reason for pruning is to try to let the light through the canopy onto the grass below. 

Trees are generally fairly hardy, but you should never trim off more than 20% of the foliage. If you prune off too much in one go, the tree will struggle to produce enough food through photosynthesis, and as a result will be unable to structurally support itself.

This becomes a serious problem if you live in an area with a lot of rain, or regular high winds, where trees have a higher chance of damage.  

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Pruning Too Close to the Trunk

If you prune branches off too close to the trunk, you will be removing the branch collar. This area looks like a bump or swelling at the base of the branch.

The branch collar has specialized cells that help the tree to repair wounds quickly and prevent the tree from getting diseases. If you prune the branch too close to the trunk, it will then be susceptible to pests and diseases, leaving the tree vulnerable.

You should also be careful to avoid bark tears when you are pruning. Make a clean cut through when you are pruning, try not to tear the wood, especially if it is a young tree. 

Pruning at the Wrong Time of Year

Before you get out your pruning equipment, make sure that you research carefully if it is the right time of year for a tree to be pruned. This varies depending on the species and the type of climate that you live in.

If the branches of your tree are facing the west, they shouldn’t be pruned in the hot summer months. Many species of tree, including maples and red oaks are also susceptible to sun scald, so should only be pruned in spring and fall, when the weather is cooler.

In the southern states of America however, oak trees shouldn’t be pruned between February and June, or they can spread oak wilt disease. 

Cutting Off the Top of the Tree

common pruning mistakes

We cut the tops of trees, in particular conifers and pines, to simply reduce the height. However, in doing this, it will encourage the trees to produce leaders - large dominant branches growing on the outside of the tree.

These leaders will sadly only compromise the structural integrity of your tree. If a tree just has one dominant trunk without leaders it will be stronger against heavy winds, rain and snow.

The only way to fix the problem of dominant leaders is to bend them upward, using tape to attach them to the main trunk of the tree. If you can in future, try not to prune the entire top off a tree. 

Make Sure to Avoid These Pruning Mistakes

Pruning trees is essential to help them grow strong and stimulate new growth. You should try and avoid these common pruning mistakes and always do your research on the type of tree you are cutting before you get out the shears. 

About the Author Ann Katelyn

I'm Ann Katelyn, Creator and Chief Author of Sumo Gardener. Since I was a child I've always been fascinated with plants and gardens, and as an adult this has developed into my most loved hobby. I have dedicated most of my life to gardening and started Sumo Gardener as a way to express my knowledge about gardening with the hope of helping other people's gardens thrive.

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