Red Acer Pal Leaves are Wilting

[Rateeluck]

Hello,

I have around 10 red JM and a few of them are starting to look a bit sad.

Last year:
All my maples got a bad bout of powdery mildew and the leaves dropped in early fall

This year:
I repotted everything when the buds were starting to push in March (zone 7). They were in potting mix and I switched everything over to fast draining bonsai mix. First flush on all trees was looking great. Was watering every 2 days. The healthy trees leaves are just starting to harden off.

Here's some pictures. Maybe this is root failure? I don't see any pests or signs of disease. Any help is appreciated.

Weakening leaves:


Worst ones:


Healthy ones:

 

[penumbra]

I am wondering what you mean exactly by "when the buds were starting to push". There is definitely a problem.

 

[Rateeluck]

Good catch. Before the buds were starting to swell is when they were repotted.

Thanks

 

[penumbra]

Planting time sounds ok so I am thinking root damage. Can't say why as there are several possibilities.

 

[Rateeluck]

When I repotted, I didn't cut many roots if any. Hopefully the rest make it. The sick guys are in the shade. I think they used up their reserves on the first flush of leaves. I doubt there's enough energy to push anything new.

 

[Vance Wood]

Are you sure you are watering enough?

 

[Ohmy222]

is it black near the roots? Maples will sometimes die at the roots in early spring. They will leaf out, look beautiful, and then promptly die. Hope it is not this but definitely see if you have black on the lower trunk and maybe scratch for some green.

 

[sorce]

I don't think underwatering is the problem, though it wouldn't hurt (regularly) to water more.

I do think repotting time was too early, especially for plants that are basically tapped, as indicated by the early leaf drop last year.
They dropped those leaves early because the return on keeping them wasn't enough.

That need for energy return doesn't go away till at least mid summer. If not the whole year.

So not only was the repotting "early", for those stuck believing spring repotting is the only safe time, but it shouldn't even have occurred.

Sorce

 

[Deep Sea Diver]

Maybe there is some missing information.

1. How much root trimming did you do? Do you merely “wash and fill with new media”, trim back the roots.... or go full bore Ebihara on these trees?

2. How much direct sun hours are these guys getting. 10, 8, 6, 4 hours? ...and are all in the same location?

3. Also if sunlight is partial day, is it AM, Midday, or PM sun

cheers
DSD sends

 

[Potawatomi13]

Maybe there is some missing information.

1. How much root trimming did you do? Do you merely “wash and fill with new media”, trim back the roots.... or go full bore Ebihara on these trees?

When I repotted, I didn't cut many roots if any! DUH!

 

[Potawatomi13]

Suggest to spray well with Daconyl then keep in largely shady area a week or so. This can be hard on new leaves. Having some leaf mildew problem here spraying well before bud break works pretty well. Any done ON leaves is done under shady conditions/cooler weather.

 

[SeanS]

Still watering every 2 days? The fact that all of them are showing the same symptoms leads me to believe it’s a problem with something you are doing to all of them, namely possibly your watering

 

[Deep Sea Diver]

When I repotted, I didn't cut many roots if any! DUH!

Gosh I guess I missed that point. Thanks for so very politely pointing this out.

The other two points I noted are still valid. My bet is that the trees were in put too much sun right after the repot. The same thing just happened to me. Some trees weren’t affected right off, others were.

After realizing the trees were especially sensitive and getting fried I put them in the shade. About 1/2 the affected trees recovered so far.

cheers
DSD sends

 

[Rateeluck]

Thanks for all the replies. I will try to answer them here:

I don't water is an issue. I never go more than 2 days and I check on them daily by scratching the top layer of soil to see if it's dry below the surface.

I didn't cut many roots off when repotting. I shook off the old dirt. Did not rinse with water to totally clean the roots.

Sun is 6 hours per day. Morning from 9 to around 2 or 3pm.

I have about 10 or so of these red guys and all were and are treated the same. Only 3 have these symptoms.

I scratched the wood of the trunk and they are green.

I sprayed the trees with diluted line sulphur when the buds were swelling as suggested on this forum. I can spray with Daconil but I don't see any signs of fungus.

I did not shade the trees after repot. Maybe that's the issue. I put them in the same spot they are now.

I have many other maples (30 or so), tridents and APs. All were changed to bonsai mix and repotted and given the same treatment as these red APs.

Thanks again for all the help

 

[Vance Wood]

When I repotted, I didn't cut many roots if any! DUH!

There is one thing not considered; often J Maples will produce wilty looking foliage in the Spring that will fill out as the leaves mature. It is better to believe this than to kill the tree with extravagant measures to cure the tree of imagined diseases.

 

[0soyoung]

The blackishness shown in this pic is ominous as are the light brownish spots associated with it. I rather expect that every tree with leaves that suddenly wilted are similar. When the cambium of a JM dies it causes the bark color to change to a blackish tone, When it is subsequently desiccates, the bark turns light brown and even whitish. The other thing that goes with dying cambium is that they signal to the living cells in the nearby wood to clog the xylem to compartmentalize damage. Should this perceived damage be so extensive as to cause the entire stem's wood to be clogged, the foliage is effectively cut off from the roots --> is suddenly wilts, withers, and eventually dries. These leaves will stay attached when they ultimately turn crispy brown because there is no life to produce the membrane that allows the petiole to separate from the stem.

It likely was caused by a pathogen. Since it apparently happened over the winter, pseudomonas is a suspect cause, especially if there is no apparent bark damage, such as a cut that exposed wood.

 

[Rateeluck]

The blackishness shown in this pic is ominous as are the light brownish spots associated with it. I rather expect that every tree with leaves that suddenly wilted are similar. When the cambium of a JM dies it causes the bark color to change to a blackish tone, When it is subsequently desiccates, the bark turns light brown and even whitish. The other thing that goes with dying cambium is that they signal to the living cells in the nearby wood to clog the xylem to compartmentalize damage. Should this perceived damage be so extensive as to cause the entire stem's wood to be clogged, the foliage is effectively cut off from the roots --> is suddenly wilts, withers, and eventually dries. These leaves will stay attached when they ultimately turn crispy brown because there is no life to produce the membrane that allows the petiole to separate from the stem.

It likely was caused by a pathogen. Since it apparently happened over the winter, pseudomonas is a suspect cause, especially if there is no apparent bark damage, such as a cut that exposed wood.

Could this spread to other trees? Guess there's no treatment?

Thanks

 

[0soyoung]

Could this spread to other trees? Guess there's no treatment?

Thanks

At this point, I think not. However, pseduomonas-like infections aren't necessarily death sentences for landscape trees, and maybe not even (pre-)bonsai. But an ounce of prevention is worth at least a pound of cure. Since the effects have been progressive this spring, it is likely that the affected trees are just sources of further infection (by whatever the pathogen is). Of course, there is the possibility that the pathogen is no longer present and just that its effects became manifest at the trees woke up, but the dead trees no longer serve any productive purpose. So, ...

However, I suggest that as you discard them, you do a little autopsy on them - be sure to sanitize your cutting tools afterward. I think if you cut the stems above the black that you will find the wood a normal bright creamy-white. You should see some discoloration(s) immediately above and in the black region. When the parenchyma or living cells in the wood die, the wood changes to a grey color and compartmentalization lines separating grey from whiteish are usually darker. Cosmic conclusions are unlikely, but I do this sort of thing every time a tree/layer dies on me - with time/experience it starts to add up and become quite illuminating, IMO. Again, be sure to wipe down the cutters with 70%+ isopropyl, say, after you're done with them.

 

[Rateeluck]

The 'Weakening leaves' pictured tree From post #1 are starting to look better. I had wrote this guy off but seems to be making a recovery. Been in shade for a few weeks and watering regularly. I tried to disect the other two that died but I didn't see any real color difference inside the wood