My plum tree is rotting where a branch was cut some time ago. The rotting zone had what looked like soil with worms and wood lice.

I cut out the affected the region but it is affecting almost 1/3 to half the diameter of the trunk.

I have sprayed a neem oil and insecticidal soap solution, and I have bought a wound sealant too, which I plan to use.

There are other places on the tree where the bark/skin is split and a similar problem is occurring.

What would you suggest?

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3 Answers 3


This is not looking good - the photograph appears to be showing an area on the main trunk, but it's not clear whether this area is near the base of the plant or much higher up, though I suspect it's the latter (near the base). If it's high up, then remove back to healthy wood, but if this wound is towards the bottom of the tree, and the same issue is appearing elsewhere, it's not looking hopeful for the tree's healthy survival. Further, as it gets worse, there's a strong risk of it suddenly falling in high winds, so its proximity to buildings and/or people nearby is a consideration if it's quite tall.

I'm not seeing any weeping, but I do wonder if that area is soft, so you might try pushing the tip of a pen or biro into it - you should not be able to penetrate it if its healthy. Otherwise, it's probably worth posting a photo showing the whole plant so its easier to tell quite where this problem is, or give more information regarding the age of this tree, its height and spread and the location of this wound.

Wound paints are no longer recommended - they don't prevent problems occurring at a wound site, and may actually increase the likelihood of problems occurring, so don't bother to use it.

  • The base of the tree is not much further down than what the first picture shows (another 15-20cm), so the wound site is about a meter up. The tree is not near anyone, so I am not bothered about it falling. However, if I cut out the wound, what do I cover it with/treat it with, if any? Thank you. Mar 13, 2017 at 14:32
  • 1
    Just leave it alone, don't cut away any more or you'll compromise healthy tissue, if there's any left, and don't treat or cover with anything - wound paint, as I said, is no longer recommended. It's too near the base of the plant to cut back beyond this point, so just let it be and see how it does this year.
    – Bamboo
    Mar 13, 2017 at 20:17

Cut the tree and burn the wood, otherwise the disease might spread to other plants.

Edit: The reality is that

  1. The tree's life will be shorter than the life of a healthy tree.

  2. The disease is spreading, according to the OP.

  3. The reserve of pathogens builds up.

In this case, I would try to minimise the risk to other plants in the garden and that's why I said to cut the tree, although I know this is the least pleasant answer somebody wants to hear.

  • They'd have to get tests done to find out the exact disease or problem. Trees have their own methods to deal with disease and if left alone will end up with big cankers but totally healthy. Prunus is always having this problem thus the gummosus whenever it gets an owwiiiie or there are problematic insects. The tree's way to protect itself. Spreading? The world is full of the valsa canker fungus; missouribotanicalgarden.org/gardens-gardening/your-garden/…
    – stormy
    Mar 14, 2017 at 18:11
  • And I think more of us should be more able to say unpleasant things...what do you think the pathogen is and what other plants are susceptible?
    – stormy
    Mar 14, 2017 at 22:10

No treatment at all. Leave it alone. No staking either. Half the vascular system is still viable. I would THIN your tree so wind is able to go through the branches without being stopped and able to pull your tree over.

What is more problematic are those vines. I'd like to see the base of your tree's trunk. Are those vines covering it up? Is there soil or mulch on the bark of your tree? Only the roots should be in the soil. Vines, soil, mulch, rocks or moss will allow the bark to stay moist and that invites bacteria which will girdle your tree, eventually killing it. Pull all soil, mulch and vines off your bark immediately if so. Please send another picture of the base and one of the entire tree?

  • Hi, yes, all of this rings a bell. I remember tipping some soil on the roots a while back to "help it". This is a major life lesson for me. I will post a few pictures today. What is the best medium to send this? Should I edit the original post? Mar 14, 2017 at 9:55

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