Die back on Lions Head Maple

[Joe_B]

Hi all,

I’ve noticing some branch die back on my Lions Head. This was nursery stock and I cut the top off in early summer. Maybe not the best time but I didn’t think it would be too detrimental. After cutting the top two branches, I sealed them and as always, new shoots started growing upward. I now have some concern that the branches will die back into the trunk and I will loose the new shoots/top. Any ideas or recommendations?

 

[0soyoung]

Acer palmatum will inevitably die back to a node.
Acer palmatum nodes are visually obvious, almost as obvious as on bamboo.

Not to worry.

 

[63pmp]

To me it looks like you got a bacterial infection in the cut, the node were it has died back too is infected. Just have to wait and see if it travels further but if main branch to the left (picture3) starts to die you will have to cut trunk off below the infection.

It's a wait and see.

 

[clem]

Maybe something (a fungus, bacteria, virus) has entered inside the cut.
So, if the necrosis of the green tissues spreads, it is better to cut. Better to cut a finger than a hand.

This was nursery stock and I cut the top off in early summer. Maybe not the best time but I didn’t think it would be too detrimental.

In my 4 years experience in JM, the big cuts in june, july or august are very safe because the scar bead developps quickly, in a few weeks if the tree grows correctly. I think summer is the best time to perform clip & grow or big branches cut on the trunk. Better than in autumn because in autumn i don't see any scar tissue developpement. I always disinfect my tools with alcohol before to cut. I apply a thin layer of the japanese healing paste in tube, let it dry out, and then apply the putty paste. I cross fingers but untill now i have never had any infections or sapp withdrawal on my "summer" cuts.

 

[Bonsai Nut]

Make sure you seal cuts on Japanese maple, else you run a good risk of picking up a fungal infection. At this point you can wait and see if the tree continues to die back, or you can be more aggressive and prune back the dead area until you hit live bark (making sure to sterilize your pruners with each cut) and then make sure you seal the wound with a decent waterproof bonsai sealing compound.

 

[Forsoothe!]

I have a big one in the landscape and every time I cut 6 inches off it dies back a foot. There is probably a pathogen resident on the surface (I speculate). I have never had this problem anywhere else, and I've been in this game a long time.

 

[Joe_B]

Thanks all, appreciate the help. I guess I’ll wait and see for a little while. Here is a link the to cut past that I use.

Kiyonal Cut Paste & Wound Seal - Shin kiyonaru - 100g Tube

Kiyonal Cut Paste & Wound Sealant Imported From: Japan Company: Shin Kiyonaru Sizes Available: 100g tube Kiyonal is an imported Japanese cut paste that is one of the most popular in the bonsai community. Apply this to your cuts to prevent "bleeding" and keep fungus from infecting and killing...

www.superflybonsai.com

 

[Joe_B]

Hi all, wanted to give an update on this tree. As you can see, there has been considerably more die back and the upper shoots are starting to die as well. How many inches down do you think I should cut?

 

[Tums]

If it were me, I'd be conservative and cut down around this red line. One of the little branches right below would then probably become the new leader.

 

[Canada Bonsai]

My initial reaction was exactly what @0soyoung expressed, and I still lean this way.

I perform a lot of shishigashira air layers every year, which means I am constantly pruning big branches like you've done, and I often see the mechanics of what you're seeing, but I believe there are 2 factors making your situation particular and problematic:

The stub you left should have have given your tree enough time to compartmentalize the dieback and save the trunk, if the remainder of the tree--and especially the branches above the cut-site--were relatively vigorous. However, it looks like the branch that you cut and removed in the apex was very thick in contrast with its closest neighbouring branches and those remaining above it. It is possible that the young shoots above the cut-site simply didn't have the pull to contain the die back. The other factor that is particular about your situation is that it looks like the branch collar makes up about 80-90% of the trunk at that junction (see 1st image attached), and so while we normally expect dieback up to and into the branch collar, in this case that area makes up a significant majority of your trunk. This would have been less of an issue if the branches above the cut-site were much stronger (of course timing etc. are also important).

I would not be overly concerned in your situation. When I remove air layers from my shishigashiras I often see what you are seeing, although in general I try to avoid situations with compounding problematic factors like the situation you're facing now. That said, I prefer to see die back that looks like the big cut-site above the one we're discussing (see 2nd attached image), and especially at this time of year I would be concerned that a pathogen will or already has entered the tree at this weak location. I would personally cut where you indicated in your last post, with sterile tools, clean hands, and I would seal the wound.

 

[Forsoothe!]

Hi all, wanted to give an update on this tree. As you can see, there has been considerably more die back and the upper shoots are starting to die as well. How many inches down do you think I should cut?

I have a big one in the yard and every time I prune anything, it dies back a foot. I have tried everything over the years and I assume that there is a pathogen that is resident on the bark that I can't prevent from entering any cuts, so I can't touch it.

 

[Joe_B]

I have a big one in the yard and every time I prune anything, it dies back a foot. I have tried everything over the years and I assume that there is a pathogen that is resident on the bark that I can't prevent from entering any cuts, so I can't touch it.

Wow, a foot! That’s nuts

 

[0soyoung]

I assume that there is a pathogen that is resident on the bark that I can't prevent from entering any cuts

That is always possible. Pseudomonas syringae is a bacterium that is presumed to do exactly this (i.e., lounge around on the bark and to gain access into the tree by serving as a nucleation site during winter freezes). A possible way to address this is to wipe down the bark around the site to be cut with an antiseptic (peroxide or alcohol). Of course, also sanitize your cutting tool beforehand.

That might be enough, but logically we would think it is possible for pseudomonas or some other pathogen to fall onto the cut end and infect the exposed tissues. Since this could happen immediately, it seems reasonable to thoroughly wet the cut surface with an antiseptic and then apply some sealant before it has dried.

It all seems a bit excessive, but this methodology could demonstrate whether there is merit to your suspicions or not and indicate what might be an effective practice.


I bought several landscape maples (a shishigashira among them) from a grower near the Canadian border. He advised me to never cut a Japanese maple if it was going to rain in the following 3-5 days. He showed me some trees with which he had violated this rule and they all had excessive (black bark) die-back from the cuts.
Raindrops do condense on things in the air. Bacteria may be among them.

 

[Forsoothe!]

I never tried Peroxide, just 15% bleach or straight isopropanyl alcohol sprayed on directly immediately before and after and immediately painting the wound with the Japanese stuff or asphalt. Nothing made any difference. When I say die-back a foot, I mean it. Imagine what that looks like, remembering just how absolutely straight they grow anyway.

 

[Joe_B]

I’ve been so busy this season with moving I’m really late on working this tree… unfortunately it’s still dying. I cut it back in October and it didn’t show any signs of die back until spring when the dead wood slowly started going lower. All my tools were clean and disinfected, cut paste was applied after.

I’m looking to not make another mistake on this… how far down do you think I should cut this time?

First two images are from last October, all the rest are from this week.

Joe

 

[19Mateo83]

It looks like the bark is starting to try to heal over like it would at a cut site. I would see this as a good sign? I would only worry if those two top most branches die off.

 

[Jester217300]

The initial black area that was removed is likely verticillium wilt. This is a fungal disease present in most yards and will attack compromised Japanese maples. This is a weaker cultivar of JM that will routinely be subject to issues like this. Verticillium wilt can be treated with fungal spray (sulfur or the like) if caught in the early stages of infection.

The current dieback is normal. The tree has compartmentalized and is forming a callus. This is all a healthy reaction to the chop. Remove the dead wood and reseal the area.

 

[Joe_B]

Thank you both. I’ve removed the dead wood. Any suggestion on a general maple spray I could get online? I routinely use systemic pellets to fight bugs but have yet to use any sprays for specific species.