Acer Palmatum Bloodgood Leaf Scorch

[Green_lover]

Hello everyone,

I got an acer palmatum 'Bloodgood' at the end of this May and it was thriving until 2 weeks ago. It is not a very small tree, so I believe it was already established. However, the leaves started to scorch and it seams this is not stopping.
The following photo and the 2 videos at the bottom are from 5 days ago.



This is a photo from now. There are more scorched leaves now :



I repotted it in the beginning of June in a big pot - the one on the photos (with 60-65 litres of soil) and started watering it as per the nursery specialist's advice: 7-8 litres of water when the first 5-6 cm of the soil is dry and wait for the water to drain through the holes of the pot. It sounded and looked like too much to me, but hey, he's the specialist. The pot is from plastic and it has at least 12 holes (1 cm diameter each) at the bottom. I also put a 3-4 cm layer of stones at the bottom and then I put a fresh soil I bought from the nursery. So I guess this is enough for good drainage. To add, I never let water to sit in the pot dish.

However, the summer began and we've been having really hot weather here (35-36 C). The leaves started scorching, but the wierdest thing is the soil is not drying. I cannot say it's soaking, but I even bought a moisture meter and it has been showing the soil is still in the wet zone even after 2 weeks of no watering at all. The soil (the one I test when I dig 10-15 cm in the pot) feels moist to touch as well and it really confuses me how it is not drying in this hot weather. Long story short, my acer is giving me mixed signals. The soil is wet, but the leaves are dry and keep scorching. The roots do not seem rotten from what I could see.

I have a few questions:
1. What can I do to prevent this happening to my acer?
2. Does this mean my tree is already dying?
3. Should I water it now or wait more time (I repeat, it has been more than 2 weeks now and the moisture meter still shows the soil is wet). Even the soil is moist, the problem is I can still see new leaves scorching.

Important note: The location of the pot is on a balcony that is east oriented and it has direct sunlight only until 12:00-13:00. I live in Skopje, Macedonia and this summer is really hot (almost every day we have temperatures above 30 degreees celsius).

Thanks in advance to anyone who would take their time to help me!




View attachment IMG_3653.mp4
View attachment IMG_3655.mp4

 

[Jrmcmich]

Soil looks like garden soil? If so could hold too much moisture. Assumed you just slipped pot it without root work. Seems like one of hardest things to diagnose is watering as too much water and not enough water show similar results to leafs. Based on soil my guess is it’s not drying out enough between watering

 

[Shibui]

Acer palmatum can be difficult in hot, dry climates. They seem to need a lot of water to keep the leaves in good condition. On really hot days it seems they can have trouble getting enough water to feed the leaves, even if there is plenty of water in the soil. Having said that, 35-36C is not really hot. I think it is hot when daytime temps get over 40C so your temps should be OPK for JM.

The larger, deeper pot will usually protect the tree from over watering to some extent.

June is NOT a good time to repot any deciduous tree but I also assume you did not do a traditional bonsai bare root and root prune? I'll assume you just slip potted - take tree out of one pot and place the intact root ball into a bigger pot and full with more soil? Did you do any root cutting or tease out any of the roots when potting this tree?
Slip potting can sometimes cause problems, especially if the new soil is quite different from the old root ball. Neither water or roots seem to be able to cross a defined boundary in the soil which is why we are told to tease roots of potted plants when slip potting or planting them in the ground. The roughened soil boundary helps new soil make better contact with the old root ball and a few roots already into the new soil helps the roots start to move out into new soil.

I have just checked the soil video. The soil appears to be quite dry. It does make a lump when squeezed but barely and no water comes out so it is not very wet. I know that 'wet' and 'dry' are relative terms but we need to remember that JM are trees from mountain valleys where they have roots in relatively constantly damp soils. I would usually water JM when the soil gets to that dry.
The physical amount of water we add each time is not relevant. Plenty of water ensures that it penetrates right into the middle of the pot where it is needed. Any excess should drain out of the pot so 7-9 litres of water at each watering is good. Water running through the soil and out of the pot is also good. That helps flush out waste products and helps draw fresh air into the soil. Always best to add enough water to penetrate right through the root zone and run out the bottom.
Having the pot sitting in water is not good so if it has a tray underneath make sure that does not always have water in it.
Much more important is frequency of watering. Check soil moisture as you have been doing to decide how often to water. Constant soggy soil is bad for most plants but so is dry soil. I usually keep on the wet side because dry will kill a tree in just a few hours while wet usually takes months for root rot to start and to kill a tree.

The soil you have used appears to be garden soil? While it is possible to learn to manage to keep trees in pots in garden soil it is not so easy because garden soil does tend to stay wet and packs down leaving fewer spaces for air and water. That's why growers have developed potting soil mixes which have bigger particles with plenty of spaces for air.

It is always hard to diagnose the difference between too wet and too dry without seeing and feeling the plant and soil but generally burned leaves in summer is 99% likely to be dehydration. I would increase watering frequency and cross fingers.
The damaged leaves will not recover. That damage is permanent but, all being well, the tree should grow new leaves. Your aim is to keep any new ones in good condition. The damaged leaves will not hurt the tree and probably still have enough life left to feed the tree a little but if burned leaves look offensive you can cut off the worst ones to make it look better. Badly damaged leaves usually drop off naturally as the tree grows new, healthy leaves.

For now please water your pot well. Then we need to find out more about how you 'repotted' the tree and what soil has been used.

 

[Orion_metalhead]

The fact you are only getting a few hours of sun should rule out scorch, imo. Given the soil as Shibui said, probably needs better watering practices. I agree with everything he said.

 

[Green_lover]

Acer palmatum can be difficult in hot, dry climates. They seem to need a lot of water to keep the leaves in good condition. On really hot days it seems they can have trouble getting enough water to feed the leaves, even if there is plenty of water in the soil. Having said that, 35-36C is not really hot. I think it is hot when daytime temps get over 40C so your temps should be OPK for JM.

The larger, deeper pot will usually protect the tree from over watering to some extent.

June is NOT a good time to repot any deciduous tree but I also assume you did not do a traditional bonsai bare root and root prune? I'll assume you just slip potted - take tree out of one pot and place the intact root ball into a bigger pot and full with more soil? Did you do any root cutting or tease out any of the roots when potting this tree?
Slip potting can sometimes cause problems, especially if the new soil is quite different from the old root ball. Neither water or roots seem to be able to cross a defined boundary in the soil which is why we are told to tease roots of potted plants when slip potting or planting them in the ground. The roughened soil boundary helps new soil make better contact with the old root ball and a few roots already into the new soil helps the roots start to move out into new soil.

I have just checked the soil video. The soil appears to be quite dry. It does make a lump when squeezed but barely and no water comes out so it is not very wet. I know that 'wet' and 'dry' are relative terms but we need to remember that JM are trees from mountain valleys where they have roots in relatively constantly damp soils. I would usually water JM when the soil gets to that dry.
The physical amount of water we add each time is not relevant. Plenty of water ensures that it penetrates right into the middle of the pot where it is needed. Any excess should drain out of the pot so 7-9 litres of water at each watering is good. Water running through the soil and out of the pot is also good. That helps flush out waste products and helps draw fresh air into the soil. Always best to add enough water to penetrate right through the root zone and run out the bottom.
Having the pot sitting in water is not good so if it has a tray underneath make sure that does not always have water in it.
Much more important is frequency of watering. Check soil moisture as you have been doing to decide how often to water. Constant soggy soil is bad for most plants but so is dry soil. I usually keep on the wet side because dry will kill a tree in just a few hours while wet usually takes months for root rot to start and to kill a tree.

The soil you have used appears to be garden soil? While it is possible to learn to manage to keep trees in pots in garden soil it is not so easy because garden soil does tend to stay wet and packs down leaving fewer spaces for air and water. That's why growers have developed potting soil mixes which have bigger particles with plenty of spaces for air.

It is always hard to diagnose the difference between too wet and too dry without seeing and feeling the plant and soil but generally burned leaves in summer is 99% likely to be dehydration. I would increase watering frequency and cross fingers.
The damaged leaves will not recover. That damage is permanent but, all being well, the tree should grow new leaves. Your aim is to keep any new ones in good condition. The damaged leaves will not hurt the tree and probably still have enough life left to feed the tree a little but if burned leaves look offensive you can cut off the worst ones to make it look better. Badly damaged leaves usually drop off naturally as the tree grows new, healthy leaves.

For now please water your pot well. Then we need to find out more about how you 'repotted' the tree and what soil has been used.

Hello Shibui and thanks a lot for your thorough and thoughtful insights!

First of all, I'd like to say I am very new to gardening (if you could call it that way when you have one tree on the balcony and a few plants inside your home), so all of your suggestions are welcome!

And you were right, I simply took the tree with all the soil from the old pot and put it in the bigger pot with more soil. I was not even aware I should do something else with the roots and was not aware that could cause a problem. Is there anything I could do now on that matter or it is too late (and hot)?
Regarding the soil: 1/2 of the soil I used was the most common regular organic potting soil with perlite and the other half of the soil I used is called "7-component optimal spoil for potted plants" and here is what is says in the description I found online (AI translated): Special seven-component soil, ready for immediate planting and transplanting of all types of potted plants and indoor plants. It contains: white and black peat, which provide a light substrate in which the roots develop well or regenerate quickly. The plants are healthy, strong and abundantly flowering, and natural compost maintains the right ratio of organic mass. Wood fibres, which enable a very airy structure with optimal water and air passage and improve the structure of already existing substrates, a high-quality additive made of pure volcanic stone (perlite) which acts as a moisture retainer, so we water less than usual, calcium fertilizer (lime) which maintains the appropriate pH and prevents acidification of the substrate. At the same time, Ca is also an important plant nutrient that makes other nutrients available to plants. It also contains more soluble, long-acting nutrients that are absolutely necessary for normal plant growth, their content is adapted to the needs of plants. Growth and flowering activators that stimulate the growth, development and abundant flowering of plants.

My biggest concern is that on all the forums I found it was written that JM should be wattered more frequently in pots, especially in summer, but to still let the soil dry out between waterings. But my soils stays wet for more than a week between waterings even in the summer! And yet again, the leaves are continuously drying and scorching. :/ As you mentioned, "dry" and "wet" are very relative and that is why I bought the moisture meter, which still goes up to the fully wet side (even though it has been 2 weeks since I last watered the tree).

When you say "I would usually water JM when the soil gets to that dry" above, what do you exactly mean by "that dry" - the level of dryness of the soil on my video?

Thanks!

 

[Green_lover]

Soil looks like garden soil? If so could hold too much moisture. Assumed you just slipped pot it without root work. Seems like one of hardest things to diagnose is watering as too much water and not enough water show similar results to leafs. Based on soil my guess is it’s not drying out enough between watering

Thanks a lot for your reply!
I wrote about the soil mixture in one of the other replies. And yes, I didn't do anything to the roots when I repotted it. :/

The moisture meter shows the soil is still wet, but isn't it too much for a JM to stay 2 weeks without water? Plus, my first logical idea when I see the dry leaves is that it needs more water. Is it possible to have this outcome from overwatering?

Thanks again!

 

[Green_lover]

The fact you are only getting a few hours of sun should rule out scorch, imo. Given the soil as Shibui said, probably needs better watering practices. I agree with everything he said.

Thanks for your reply!

When you say "better watering practices" do you mean more water and more frequent watering? If, so how much and how often?
The biggest problem is how to fugure out what is "dry" for my JM and not kill it finding out... :/

 

[Shibui]

When you say "I would usually water JM when the soil gets to that dry" above, what do you exactly mean by "that dry" - the level of dryness of the soil on my video?

I would definitely water when the soil reached the level of dryness I seem to see in the video.
I am a little concerned that your moisture meter says wet while I am saying dry. I'm definitely a long way away from you and only working from photos but that and gut feeling is the best I have.

, I simply took the tree with all the soil from the old pot and put it in the bigger pot with more soil. I was not even aware I should do something else with the roots and was not aware that could cause a problem. Is there anything I could do now on that matter or it is too late (and hot)?

After a week, maybe after 2 weeks but 4-5 weeks is probably a little too late to redo the potting, just in case I am wrong and the roots are already spreading out into the new soil.

Glad to hear you have used proper potting soil for your pots. It does not look like any potting soils we get here but conditions are vastly different from place to place so I trust that your companies know what they are doing.

Having explored those factors I'm afraid I have little more to offer.

 

[Jrmcmich]

Thanks a lot for your reply!
I wrote about the soil mixture in one of the other replies. And yes, I didn't do anything to the roots when I repotted it. :/

The moisture meter shows the soil is still wet, but isn't it too much for a JM to stay 2 weeks without water? Plus, my first logical idea when I see the dry leaves is that it needs more water. Is it possible to have this outcome from overwatering?

Thanks again!

Does it get decent sun to help dry out soil? If staying wet for weeks seems will be challenging to water right but also not sure if good idea to change soil again when stressed. At least you didn’t do root work. Ideally you may have added larger perlite or pumice to soil to help with drainage. Maybe someone else will chime in. Did you up size pot when repotting? Maybe pot size a bit large for root ball?

 

[rockm]

Hello Shibui and thanks a lot for your thorough and thoughtful insights!

First of all, I'd like to say I am very new to gardening (if you could call it that way when you have one tree on the balcony and a few plants inside your home), so all of your suggestions are welcome!

And you were right, I simply took the tree with all the soil from the old pot and put it in the bigger pot with more soil. I was not even aware I should do something else with the roots and was not aware that could cause a problem. Is there anything I could do now on that matter or it is too late (and hot)?
Regarding the soil: 1/2 of the soil I used was the most common regular organic potting soil with perlite and the other half of the soil I used is called "7-component optimal spoil for potted plants" and here is what is says in the description I found online (AI translated): Special seven-component soil, ready for immediate planting and transplanting of all types of potted plants and indoor plants. It contains: white and black peat, which provide a light substrate in which the roots develop well or regenerate quickly. The plants are healthy, strong and abundantly flowering, and natural compost maintains the right ratio of organic mass. Wood fibres, which enable a very airy structure with optimal water and air passage and improve the structure of already existing substrates, a high-quality additive made of pure volcanic stone (perlite) which acts as a moisture retainer, so we water less than usual, calcium fertilizer (lime) which maintains the appropriate pH and prevents acidification of the substrate. At the same time, Ca is also an important plant nutrient that makes other nutrients available to plants. It also contains more soluble, long-acting nutrients that are absolutely necessary for normal plant growth, their content is adapted to the needs of plants. Growth and flowering activators that stimulate the growth, development and abundant flowering of plants.

My biggest concern is that on all the forums I found it was written that JM should be wattered more frequently in pots, especially in summer, but to still let the soil dry out between waterings. But my soils stays wet for more than a week between waterings even in the summer! And yet again, the leaves are continuously drying and scorching. :/ As you mentioned, "dry" and "wet" are very relative and that is why I bought the moisture meter, which still goes up to the fully wet side (even though it has been 2 weeks since I last watered the tree).

When you say "I would usually water JM when the soil gets to that dry" above, what do you exactly mean by "that dry" - the level of dryness of the soil on my video?

Thanks!

You're approaching this tree like it is a "potted plant" indoors. It's not. It is a tree outside. That requires different soil. Potted plant soil compacts, has extremely small particles and doesn't drain all that well. Bonsai outside require an open structed soil made from components that both drain well, but hold onto a certain amount of water that is released over time.

Potted plant soil will become extremely hard to rewet once it dries out. That is happening with your tree--the top is extremely dry while the interior seems to be moister. The top layer is likely shedding water to the sides and draining against the pot walls, instead of penetrating the soil mass interior. That can lead to excessive drying out of the interior root mass. The soil needs to be replaced with a more open porous mix. Unfortunately, that can't be done with the tree in leaf. Repotting maples is done in early spring before leaves emerge.

I would find a deeper container big enough to hold the pot you have. The larger container should hold water. Fill it up and submerge the tree pot into it. Allow it to sit for ten or twenty minutes until the bubbling from the root mass stops. After that, pull the tree pot out (it's going to be extremely heavy), and allow it to drain thoroughly. The submersion will wet the entire root mass through. After that, I would cover the top of the pot with a white towel to prevent the sun from drying out the surface and returning to the problem. Limit excessive sun exposure (three hours of morning sun is plenty for this tree in your climate). Afternoon shade. From now on Water AS NEEDED, skip the moisture meter. They're not all that reliable. Insert five or six wooden chopsticks into the soil surface five to six inches down. Those van be used to check interior soil moisture--if the bottom two thirds looks dry when you pull them up, tree needs to be watered. If they look wet, it doesn't.

Next spring, plan on repotting the tree into better soil

 

[Green_lover]

Does it get decent sun to help dry out soil? If staying wet for weeks seems will be challenging to water right but also not sure if good idea to change soil again when stressed. At least you didn’t do root work. Ideally you may have added larger perlite or pumice to soil to help with drainage. Maybe someone else will chime in. Did you up size pot when repotting? Maybe pot size a bit large for root ball?

I thought it did get enough sun. From sunrise until 12-13. It's in shade in the afternoon. I read somewhere that this is ideal for a JM.
Talking about the pot size, this is another thing that starts concerning me. The pot I bought the tree in was not bigger than 15 litres. This one is around 60 litres (The sales person told me it's 45, but it turned out to be bigger).

I guess at this moment I have 3 options:

1. Wait more before I water it (until the moisture meter starts showing that the soil is at least medium moist) - it may take one more week and it will be 3 weeks without water!
2a. Water it now, but with not more than 1-2 litres and do that more frequently, depending on the moisture after 2-3 days.
2b. Water it now, but with the regular 7-8 litres like before and continue doing that every week during the summer, like before (the dryness of the soil between waterings would be like the one on the first video).

Your advice which one of the options to choose is most valuable to me!

 

[Green_lover]

I would definitely water when the soil reached the level of dryness I seem to see in the video.
I am a little concerned that your moisture meter says wet while I am saying dry. I'm definitely a long way away from you and only working from photos but that and gut feeling is the best I have.


After a week, maybe after 2 weeks but 4-5 weeks is probably a little too late to redo the potting, just in case I am wrong and the roots are already spreading out into the new soil.

Glad to hear you have used proper potting soil for your pots. It does not look like any potting soils we get here but conditions are vastly different from place to place so I trust that your companies know what they are doing.

Having explored those factors I'm afraid I have little more to offer.

Hello,

I am attaching 2 videos I took just now.
The moisture meter is still showing wet, although the first 3-4 cm look very dry.

I guess at this moment I have 3 options:

1. Wait more before I water it (until the moisture meter starts showing that the soil is at least medium moist) - it may take one more week and it will be 3 weeks without water!
2a. Water it now, but with not more than 1-2 litres and do that more frequently, depending on the moisture after 2-3 days.
2b. Water it now, but with the regular 7-8 litres like before and continue doing that every week during the summer, like before (the dryness of the soil between waterings would be like the one on the first video).

Your advice which one of the options to choose is most valuable to me!

Thanks!

 

[Green_lover]

Thanks

 

[rockm]

I thought it did get enough sun. From sunrise until 12-13. It's in shade in the afternoon. I read somewhere that this is ideal for a JM.
Talking about the pot size, this is another thing that starts concerning me. The pot I bought the tree in was not bigger than 15 litres. This one is around 60 litres (The sales person told me it's 45, but it turned out to be bigger).

I guess at this moment I have 3 options:

1. Wait more before I water it (until the moisture meter starts showing that the soil is at least medium moist) - it may take one more week and it will be 3 weeks without water!
2a. Water it now, but with not more than 1-2 litres and do that more frequently, depending on the moisture after 2-3 days.
2b. Water it now, but with the regular 7-8 litres like before and continue doing that every week during the summer, like before (the dryness of the soil between waterings would be like the one on the first video).

Your advice which one of the options to choose is most valuable to me!

GET RID OF THE MOISTURE METER. It is obviously not giving an accurate read on what's going on. Relying on it and not your eye is leading to some very bad places for the tree. I'd also skip trying to guess how much water you're going to use to work. Submerge the pot, get the root mass evenly moist and work from the point of knowing the pot has adequate water, not guessing what the conditions are where you can't see. Initial submersion will put you at a uniform starting point.

Your soil is the problem--less sun in hotter climates is better than too much for Japanese maples. They are understory trees in their natural habitat and are adapted to open shade and not a lot of direct sun. The sun exposure is also causing the drying out of the top of your soil. It is baking the top two or three inches and likely preventing even distribution of the water you're adding.

 

[Green_lover]

GET RID OF THE MOISTURE METER. It is obviously not giving an accurate read on what's going on. Relying on it and not your eye is leading to some very bad places for the tree. I'd also skip trying to guess how much water you're going to use to work. Submerge the pot, get the root mass evenly moist and work from the point of knowing the pot has adequate water, not guessing what the conditions are where you can't see. Initial submersion will put you at a uniform starting point.

Your soil is the problem--less sun in hotter climates is better than too much for Japanese maples. They are understory trees in their natural habitat and are adapted to open shade and not a lot of direct sun. The sun exposure is also causing the drying out of the top of your soil. It is baking the top two or three inches and likely preventing even distribution of the water you're adding.

(Sorry, below is my reply to your first post, it came up as a separate message)

Thanks a million!

The thing is I didn't know there were that many types of soil, so I went with anything a lady in a local flower shop told me and sold me. Maybe that was wrong...
That is happening with your tree--the top is extremely dry while the interior seems to be moister - that is exactly what is happening. However, when I dig more I can touch the soil around the roots and it seems quite moist.

The idea with a bigger container with water sounds good. But I am afraid my problem is that my soil is still wet even after more than 2 weeks and, as a lot of people say, overwatering is very bad for the JM. If I do that, I am sure I'll have to wait for at least a month for it to partially dry out. Another thing to mention is this is a pretty big pot (60-65 litres with a 50 cm diameter and 40 cm of hight) - it is pretty heavy already. Not sure I could do the 'transfer' that easily. On the other hand, when I put 7-8 litres of water, the soil gets completely wet - like mud, so isn't that doing the trick of submerging the whole pot in a 'pool' of water?

I was doing the stick and finger test before I bought the moisture meter and I think the results were pretty much the same. 10 days without watering and the soil was still wet (you can see the soil after 1 week of no watering on my first original post).

I will definitely think of repotting in better soil next spring, but I worry the tree won't survive... :/

 

[Jrmcmich]

Agree with rockm as looking at video it sure does appear dry. I like his idea of wood sticks used to check true moisture below 5-6” as he said. That is probably best way amd can have multiple points to observe moisture level. As he mentioned you may be getting water to sides but not in actual root ball. All this hard based on photos but that last video sure looks dry

 

[yashu]

I came to say what @Shibui mentioned already… those moisture meters are notoriously inaccurate to begin with and all but useless in an actual bonsai soil.

 

[Dabbler]

You sure that's a bloodgood - I have a couple and their leaves are deep purple and the ones I have are pretty tough for a Japanese maple

 

[AcerAddict]

@Green_lover, you've already gotten plenty of good feedback, so I'll just leave 2-cents here. Too much sun/heat combined with too little water equals a bad time for Japanese Maples. When they're in a pot as opposed to the ground, it's better to have very well-draining soil that you have to water every day (or even multiple times a day) in the summer as opposed to very heavy, "muddy" soil that stays wet for several days. JMs require an often delicate balance of sun/shade/soil/water/fertilizer in order to be happy. It can be tough to find the right combo, but very rewarding once you do. Keep at it, and good luck with this tree!

 

[Orion_metalhead]

This may sound like heresy, buuut given your top soil is drying out too fast, consider watering so thoroughly so that the whole tree is completely saturated... then, cover the top of the soil with a woodchip mulch.

This will stop the top soil evaporation and help even out the moisture throughout the substrate. Then, do not water until the soil is completely dry down 2 or 3 inches into the soil under the mulch.

Idk how other experienced members (rockm, shibui) feel about this. Next year repot into proper fast draining soil.

or, if you want to take a chance (which you may need to now that the leaves on your tree sound like a box full of candy wrappers) do a proper repot now but do not trim any roots, leave as much of the root mass as you can but clean the soil away gently.

I honestly dont know what I would do in your situation.