New Japanese Maple Struggling

[DeepSouth]

I acquired a couple of mature japanese maples at an auction a couple of months ago. One was, and still is, very healthy. The other not so much. Looking back, I realize I probably should not have purchased it as I noticed it had several issues at the auction, but alas, it does not seem severe enough to not be curable (at least I hope).

It had several decaying/crispy leaves at auction. Over time, it has lost at least 35% of its leaves and the new ones that are growing are are turning black and crisping up. I have kept the tree in a mostly shady area with consistent watering. I have other acer palmatums in my collection that have done well in this particular location of the garden.

The leaf blackening seems to start either at the edges of the leaves or near the petiole, spreading out through the veins. Eventually the entire leaf dies.

I initially thought it was fungal. I have been spraying with daconil regularly and have treated the tree with systemic fungicide (Bonide Infuse granular) to no avail.

I have a few others with similar symptoms, though not to this extreme extent.

This species tends to struggle here in late Summer (I still consider us to be in Summer), but this seems pretty extreme.

New Leaves:



This is what they look like before they fall off:

 

[akillas]

I am also on the border of 8b and 9a, and these last few years have become quite inhospitable for acer palmatum.
I would say you have roots shutting down, either compaction, or overheating.

Tell us about the soil.
Did you acquire it from a northern(more temperate) location?
Did you take it out of the pot to inspect the roots?
Is the pot plastic or clay?
Does the pot sit on a hot surface?

I also lose some new growth in very hot days, even on heat/sun resistant cultivars and under shade cloth, and it looks similar to this-inability of the root to supply enough water to the leaf, either due to rapid water loss from the foliage, or roots shutting down from lack of oxygen/overheating. I would venture the second in your case

The ones that have a coarser inorganic substrate fare way better(almost no foliage loss) because i can water them 2-3 times a day, cooling them down, and roots breathe easier.

 

[DeepSouth]

The soil appears to be mostly or all inorganic. It is fairly coarse, but most grains less than 1/4”, so not as coarse as some of the substrates that I use.

The pot is a mica pot that is beginning to break down. The tree is in mostly shade so should not be getting too hot.

I do plan to repot them in the Spring with fresh soil and a new pot.

It looks pathogenic to me. I too have issues with scorch from heat and Sun, but this is presenting differently. I am also noticing some twig for back as well, which is making me think pseudomonas?

Here is a picture from today.

 

[akillas]

None of my trees ever had this, so i dont know this bacteria pattern. It certainly doesnt look fungal to me, it lacks basic symptoms.

It sounds like the soil is fine (if you lifted it and saw it wasnt compacted)
If it is pseudomonas, its hard to cure..It never really goes away, every time you stress (bonsai train) the tree, it comes back. If the guy sold it to you in a dry period and masked its symptoms, i would return it.

 

[DeepSouth]

Dang. Well, I am going to try treating it with Phyton 27 and streptomycin, removing anything that looks infected, and just leave it alone for the next year of growth.

Pseudomonas appears to be fairly ubiquitous among most plants and targets weak ones. Considering the fact that Acer p. always weakens here from the heat near the end of summer, I suspect that I won't ever fully resolved the problem.

 

[akillas]

You could isolate the tree, cut infected areas, keep it under cover so it gets no overhead rain, and water it only by submersion in water. A local arborist and friend recommends this method, along with something copper based as per product instructions. Never seen a full recovery though, and it can infect easily other trees. I would just get rid of it if you have more vulnerable and valuable trees.

 

[DeepSouth]

It’s a big tree, and was quite expensive. The nebari is close to 7”. I really don’t want to throw it out yet. Pseudomonas seems to be everywhere from what I’ve read, so I imagine that removing the tree wouldn’t necessarily stop other vulnerable trees from catching it anyway. I hope that treating the tree and improving the root health come Spring will help it fight off the infection.

These will be my last Japanese maples I purchase here.

I would really appreciate any advice from others who have had this issue in the past.

 

[Hack Yeah!]

@osoyoung , you've dealt with this i believe?

I would certainly isolate and treat as you've indicated is your plan.

 

[acer_p_bonsai]

Sorry to hear about your tree, DeepSouth.

Lots of great discussion above in the thread. I would recommend that you keep your focus on attempting to solve the root cause of the problem vs. treating the symptoms.

The current situation/symptoms as I understand it:
-Bacterial or fungal infection of leaves (and some branches?)
-Old unclosed wounds, unsealed but look okay.
-Dark (possibly clogged) soil. (unknown status, newly purchased tree)

We are in the risk zone, with a weakened tree, so I hesitate to offer dangerous advice; however, leaving the tree as is could make things worse. If it was my tree, here is what I would do; I'll overexplain, because I don't know your experience level, and it may be good information for new people browsing through the forum.

1. INSPECT THE ROOTS. My gut instinct is that your problem stems from a root problem. Most likely waterlogging, but hard to know for sure. I don't know your watering practices, or any other factors under the soil. The watering gets complicated with the concern over your extremely warm climate. (Someone commented earlier about large open soil allowing more frequent waterings for cooling effects and aeration.)

1. PRUNE PREPARE ROOTS. If my suspicion is correct, you will need to. Cut away any black or damaged roots. Carefully untangle any twisted/knotted roots if possible. Err on the side of caution, if they are stuck but healthy, just leave them. It is okay to use a gentle hose fountain spray to loosen and remove old soil. Our goal here is NOT to cut any healthy roots, only remove the damaged material. (Some people swear by commercial root dip treatments/medications. I have never used them.)

1. REMOVE DAMAGED MATERIAL. Cut away any damaged leaves with sterilized bonsai cutters. Also cut away any blackened/damaged branches. An aggressive step could also be to paint some of your fungal/bacterial medication into the open cuts. Seal all cuts with the glue-type cut paste.

1. WOODEN BOX, or large deep pot. Repot the tree into a large wooden box or an oversized bonsai pot with decent depth, to encourage proper drainage. Prepare the new container by laying down a 1 inch drainage layer of large sized bonsai soil. My preference is straight pumice for the drainage layer.

1. PLANTING THE TREE. When planting the tree into the new pot, sort the roots gently, with care not to break or damage any healthy roots. Add a small layer of bonsai soil over the drainage layer, then pile up some in the spot where you will place the tree. Tie the tree firmly into the new container. For an unhealthy tree, complete immobility is essential. Ensure you have a good 1/2" layer of bonsai soil covering your root zone.

1. MOSS TOP DRESSING. Top dress the tree with LIVE moss, if available. Moss does wonders for tree health. It will naturally wick excess moisture from the soil and aid in evaporative drying. Conversely, it will also protect the soil surface and prevent excessive drying. Lastly, live moss has great natural antibiotic effects, which can support the soil health. I would specifically recommend NOT top dressing with the fine/shohin bonsai soil, as this can somewhat decrease aeration at the surface, and may "help" any remaining fungus/bacteria.

1. RECOVERY PHASE. Water the tree well, and keep it in a shady spot in your garden for the next 1-2 weeks. If it remains stable, allow morning sun. Not sure how cold you get, but protect it this winter from hard freeze.

1. INSPECT/SEAL OLD CUTS. Inspect all old cuts/scars on the tree. If they do not show signs of infection, I recommend covering with cut putty. If/when the tree recovers, you can then and only then begin wound cleanup/repair. Ensure you have sterile tools for any cutting. (In this situation, I would probably bring out a cup of sterilization solution to rest my tools in between use for this entire process.)

To recap, my biggest concern is the potential root issue. If that's the problem, it will only get worse as winter approaches and temperatures drop, leading to slower evaporation and more risk of waterlogging the roots. By spring, this could be a dead tree. If the roots turn out not to be a problem, I would still rest easy at night knowing that I reset the tree to my own known soil conditions. Let me know if you have any questions on my feedback. Best of luck with your tree!

 

[Deep Sea Diver]

All is not lost. Maples are pretty darn hardy.

Sure, it looks fungal and also chlorotic. Also there is something akin to lichen on the branches… not a huge issue. Also needs a repot as the soil doesn’t look like it’s draining well. Top this with multiple applications of “cides”.

So is it an issue with the roots? Likely… yet root issues are caused by something else. The most common root issues are caused by “wet feet” (roots clogging drain hole internally or media decomposition), over fertilization, over applications of “cides”. Looks possible two out of three present.

The most probable cause is wet feet/poor drainage. So be systematic. ( Please have a good amount of bonsai soil available).

First step pull the tree out of the pot and check the media and roots.

If too wet - shake off as much of the media as possible.

If spongy roots - cut off to good root. (Spray scissors with 5%beach in water solution after each cut.)
Please do not remove a lot of roots unless absolutely necessary. You should do a proper repot in spring.

Then wash all the media out of the pot itself and make sure the drain holes are clear. Mica drills easily so take a large drill bit ((3/8”ish) and drill the hole around the inside bottom edge of the pot at each quadrant if there aren’t at least four large peripheral holes already.

Finally install wire, add media to replace the old media removed, chopstick in and tie down.

Protect for the winter and repot in spring.

Do not expect a miracle, just good drainage. Next year after a decent repot, root reduction etc the tree ought to do well. Please do not do any major reductions of branches until the following year.

Just a couple thoughts.

Cheers
DSD sends

 

[DeepSouth]

Thank you all for your suggestions. This is very helpful advice.

A local bonsai expert told me to check my tap water PH, because it is apparently hard in our area and high PH can lead to poor nutrient absorption, weakening the trees that leaves them open to infection. My other maples are showing a few signs of pseudomonas as well.

Well I purchased a quality electronic tester and the water has a PH of 8.3. I suspect this is leading to chlorosis in my maples (and other trees), making them weak and vulnerable. Because the original owner of this tree is local, I suspect the PH was high there, too.

I purchased a dosatron to correct my PH issue.

For this particular tree, I plan to:
1. Inspect the roots and try to remove anything dead/rotten.
2. Pot the tree into a wooden box with inorganic soil mix (pumice, haydite, and lava).
3. remove all infected material on the tree.
4. do a root soak and spray in Zerotol to reduce bacterial load as well as spraying with Phyton 27 and maybe streptomycin.

 

[DeepSouth]

Update: I trimmed off smaller infected branches, disinfected the cuts with isopropyl alcohol, and sealed them with wound sealer. I lifted the tree from the pots to inspect the roots, and I have to say, they don’t look very good. They were soaking wet and severely root bound. There were ants in the roots. This tree really needed to be repotted two years ago.

Improving the root system will be impossible without removing a significant amount of roots. I am debating whether I should do an emergency repot and hope for the best or just move it to a faster draining wooden box. We have about a month before our first frost, but I don’t know which is more risky.

Any thoughts?

 

[Deep Sea Diver]

Got it. Suspected as much. Got just such a technique.

Get a 1/4” long drill and drill the rootball through about 20-30x (done same 100’s of times on all types of trees. Many maples). This will solve the issue until spring repot.

Technique Notes: Best drills are concrete with rounded tips. When drilling use gentle pressure,. Allow drill to find its way through.. Start close to the trunk and work outward. Slant towards the center for the first thing to ensure the shin has good percolation.

Substitutes 1/4” metal rod. 3/8” drill bit. When all else not available try a chopstick. Does work often, but work a try.

Best
DSD sends

 

[Deep Sea Diver]

One last item. pH of the water.

• One could collect rainwater.
• An easy option is to secure a box of Citric Acid . Mix 1/3+ teaspoon of Ctiric Acid into each gallon of watering water. This should bring the pH down. (Also some CO2 out to be products. Don't water with any material that precipitates out.).

Also get a pH kit or meter to check afterwards. Anything below 7 and above about 6.6 ought to be good to go.

Cheers
DSD sends