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What's the deal with tree seal?

Published on June 26th 2019

by CandideUK. All rights reserved

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Pruning can cause stress in plants as it removes food-producing leaves, creates wounds that require energy to heal and increases vulnerability to infection by decay organisms or insects.
When trees are wounded, a natural sealing process is initiated, internally and externally. The wound calluses over by growing new wood and bark around the wounded area to create a barrier to isolate the infected area (compartmentalization), and simultaneously an internal process is activated to prevent decay.
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Some gardeners try to advance the healing process by applying wound dressing. The theory is that the paint seals the wound and prevents water or disease from entering.
Some horticultural experts question whether there are any real benefits to this practice as wound dressing can prevent the tree from naturally dealing with an injury.
Rather, good pruning practices are encouraged to maximize the tree’s ability to close its wound and defend itself from infection.
Here are a few things can do to help your tree recover after pruning.

Better pruning practices

  • Ensure that your tools are sharp - clean, smooth cuts enable the plant to heal wounds faster.
  • Sterilize pruning tools to help reduce the transmission of diseases and disinfect instruments regularly as to not transfer diseases from one plant to the next.
  • Cut broken branches below the point of injury.
  • Do not leave branch stubs. Prune broken branches back to the edge of the branch collar, but not flush with the trunk.
  • Dispose of contaminated organic material and use only disease-free mulch and compost.
  • Prune in the correct season. Avoid pruning during the warmer months when chances of infection increases. In this case, it would be beneficial to apply a wound dressing that contains a fungicide or insecticide.
  • If using tree seal, apply with a clean brush.
For more tips on pruning, tap the article below.
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Pruning tips and techniques


Although not all trees need tree seal after pruning, sometimes it is beneficial to apply wound dressing to provide a measure of protection for the tree.
Why not make your own tree seal?

Homemade tree seal recipe

Measure three parts of each of the following:
  • Diatomaceous earth
  • Composted animal manure
  • Soft rock phosphate
Step | 1
Add all ingredients to a bucket or container, depending on how much you will need. Use a clean tool to stir the mixture so all ingredients are evenly incorporated, and add water - enough to form a thick paste.
Step | 2
Use a clean paintbrush and apply the mixture to all pruning wounds. If the paste spreads evenly, the mixture is at the right consistency. Reapply if the seal is washed off by rain or irrigation.

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