Mature privet - ugly blotches forming on trunk

[Soup Dragon]

The attached picture is of the trunk on a privet I have had in a pot for around years. This blotch has appeared recently, and doesn't look good to me. Does anyone have an idea what might be happening.



Another large privet of mine died slowly several years ago, losing one branch after the other until it was gone. I'm worried that this one is on the same path.

Thanks in advance for any suggestions.

 

[0soyoung]

It definitely looks like something happened in that light tan dot - there is a crack in the bark. And it is clear that the cambium is dying around it. I don't know if it is because of something from the plant or animal kingdom, but it seems pretty clear that if one just sits and looks at it, it will, likely just get bigger, just as you fear.

So, suppose you carve the bark away, lifting off all that area, including the yellow boundary and see what you can figure out. And disinfect your knife and the area(s) where you handled this chunk of bark with 70% isopropyl alcohol (a household bleach solution works just as well but will etch your tools).

If you don't see eggs or some other sign of bugs, your worries that it is fungal would seem appropriate. No spray will cure a fungal infection because the hyphae are in the tissue of the tree and sprays basically don't penetrate - only a systemic fungicide can. While you may want to do that for the long term, I suggest that you consider 'cauterizing' the area. That is lightly burn the entire area, including the live bark boundary with a butane torch. This should kill any hyphae and forms some protective compounds. Again, only to the point of browning or a slight char. It has worked for me combating cankers in Japanese maples.

 

[Soup Dragon]

It definitely looks like something happened in that light tan dot - there is a crack in the bark. And it is clear that the cambium is dying around it. I don't know if it is because of something from the plant or animal kingdom, but it seems pretty clear that if one just sits and looks at it, it will, likely just get bigger, just as you fear.

So, suppose you carve the bark away, lifting off all that area, including the yellow boundary and see what you can figure out. And disinfect your knife and the area(s) where you handled this chunk of bark with 70% isopropyl alcohol (a household bleach solution works just as well but will etch your tools).

If you don't see eggs or some other sign of bugs, your worries that it is fungal would seem appropriate. No spray will cure a fungal infection because the hyphae are in the tissue of the tree and sprays basically don't penetrate - only a systemic fungicide can. While you may want to do that for the long term, I suggest that you consider 'cauterizing' the area. That is lightly burn the entire area, including the live bark boundary with a butane torch. This should kill any hyphae and forms some protective compounds. Again, only to the point of browning or a slight char. It has worked for me combating cankers in Japanese maples.

Just the sort of expert advice that I was hoping for. Thank you so much.

 

[Wires_Guy_wires]

Looks like it might have bumped into something or vice versa.
Judging from the missing patch of bark a bit higher up, I think that's the case.

If it was fungal, I'd expect really soft and mushy tissue and also foliage being affected due to the plant shutting down the sap stream on that compartment. You can feel if that's the case, if it isn't, then systemics will not help a lot.

 

[Soup Dragon]

It doesn't feel soft and mushy, and the foliage is OK. The only thing that might have bumped into it is a falling pine cone or an angry cat. Do plants 'bruise' like this with contact?

 

[_#1_]

Are these two holes? Looks like the larger one on the right is a hole. Maybe something got into it and killed that part. I would remove the dead section to see whats underneath.

On a side note, what kind of Privet is it? All the ones I know of has tan or gray color barks. And new shoots are reddish brown with light colored specs

 

[Soup Dragon]

Are these two holes? Looks like the larger one on the right is a hole. Maybe something got into it and killed that part. I would remove the dead section to see whats underneath.

On a side note, what kind of Privet is it? All the ones I know of has tan or gray color barks. And new shoots are reddish brown with light colored specs

I'll be able to get out into the garden on Saturday and do some investigative work to see what's going on underneath.

I'm not sure what kind of privet this is. It was used for hedging until I dug it up. The older pieces of trunk are grey, but this 'newer' piece must be about 8 years old at least. Here is what the leaves look like:



Many thanks!

 

[0soyoung]

I encourage you to cut off some of the bark in the yellow area as part of your investigation. Just cut an outline in the yellow area and lift it off. The cambium is dying where the bark is yellow and alread dead where it is brown.

The cambium is alive where the bark is green and will have to regrow across this area regardless of whether the bark remain or not.

 

[Shibui]

This dying bark could also be sunburn. It is not uncommon after pruning or styling or when the tree is moved from a shaded area to a sunny one and previously shaded bark is suddenly exposed to strong sun. Sunburn may not show up for several months so this could have happened last summer.
Physical damage is also a strong possibility, especially if it was recently dug. A hit with the spade or other tools while getting it out of the ground or a knock while transporting can do this.
Infection is also possible but less likely IMHO.
Treatment for all causes is the same as Osoyoung has specified.

Your info that another privet died slowly has me worried though. Privet are normally very hardy. You have not specified whether you keep other bonsai or where and how you look after these. Maybe you need to look at the conditions you are keeping these trees and possibly adjust care to give them a better chance?

 

[Soup Dragon]

I encourage you to cut off some of the bark in the yellow area as part of your investigation. Just cut an outline in the yellow area and lift it off. The cambium is dying where the bark is yellow and alread dead where it is brown.

The cambium is alive where the bark is green and will have to regrow across this area regardless of whether the bark remain or not.

Yes, I will do this tomorrow when I can get out into the garden. This damn work stuff is getting in the way . Thanks!

 

[Soup Dragon]

This dying bark could also be sunburn. It is not uncommon after pruning or styling or when the tree is moved from a shaded area to a sunny one and previously shaded bark is suddenly exposed to strong sun. Sunburn may not show up for several months so this could have happened last summer.
Physical damage is also a strong possibility, especially if it was recently dug. A hit with the spade or other tools while getting it out of the ground or a knock while transporting can do this.
Infection is also possible but less likely IMHO.
Treatment for all causes is the same as Osoyoung has specified.

Your info that another privet died slowly has me worried though. Privet are normally very hardy. You have not specified whether you keep other bonsai or where and how you look after these. Maybe you need to look at the conditions you are keeping these trees and possibly adjust care to give them a better chance?

It has been in a pot in my garden for 5+ years, so the opportunities for physical damage are slight. Falling pine cones are the only danger (the umbrella pines here have big, heavy cones), but even then they would have broken branches before hitting the trunk.
I have about 20 trees currently. In recent years I have lost very few. This one is the heaviest (and in a heavy pot) and so sits on a cement block on the ground rather than being on a bench (as did the one that died). This is the only difference in treatment that I can think of.
I will follow Osoyoung's suggestion tomorrow. Thanks!

 

[Jzack605]

Sunscald was my first thought as well.

was the tree moved?

 

[Jzack605]

Perhaps also antracnose/twig blight

Privet Ligustrum

portal.ct.gov

Maybe phytophothora canker as well.

 

[Soup Dragon]

I encourage you to cut off some of the bark in the yellow area as part of your investigation. Just cut an outline in the yellow area and lift it off. The cambium is dying where the bark is yellow and alread dead where it is brown.

The cambium is alive where the bark is green and will have to regrow across this area regardless of whether the bark remain or not.

Hello, I did as you suggested, and it looks bright green and healthy underneath. Is this much ado about nothing? I'm embarrassed that I might have wasted everyone's time on this.

 

[Soup Dragon]

Sunscald was my first thought as well.

was the tree moved?

It does get a lot of sun in the summer, but I haven't moved it in years.
I just mentioned on another post that the cambium looks perfectly healthy underneath the 'bruise', so maybe I am simply worrying too much. The demise of another privet a few years ago had me on edge for this one I suppose.

 

[Soup Dragon]

Perhaps also antracnose/twig blight

Privet Ligustrum

portal.ct.gov

Maybe phytophothora canker as well.

That link is really useful.
"Leaves are small, growth is slow and followed by dieback of branches and death of parts of the hedge." (root rot)
That sounds exactly like what happened to the other tree.

 

[0soyoung]

Hello, I did as you suggested, and it looks bright green and healthy underneath. Is this much ado about nothing? I'm embarrassed that I might have wasted everyone's time on this.

Now you know. Sigh of relief, huh?
Congrats.

 

[Soup Dragon]

I'm reviving this thread to add the gloomy news that the problem progressed, and the tree lost its branches one by one until there is very little left of it. In the picture below you can visibly see the last remaining stripe of live trunk surrounded by dead trunk. I am assuming a fungal issue affecting the roots, like honey fungus (Armillaria), although I'm not seeing the precise symptoms normally associated with this (from what I have read).



Anyway, this is definitely on its last legs (or last roots). I'll make sure I dispose of the soil somewhere far from other plants.

 

[Shibui]

Always sad to see a tree decline but as an optimist there is now some space for a better tree.

 

[Jzack605]

Maybe carve that all away, into living/healthy tissue. Maybe you’ll find an interesting tree in there and it’ll survive or prolong its life