Sun burn on new needles? - young larch (laricina)

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#1
So this tree was collected last fall, made it fine through the winter and was repotted in bonsai substrate in late April, when the buds were starting to show some green. It spent about two weeks in a shady spot, protected from the wind, and then I moved it around 10-12 days ago to a sunnier spot (around 5-6 hours of mostly morning and midday sun). Does this look like sun burn to you, or could it be another problem? It is affecting the first needles to come out, in the the top of the tree, while the newer ones (mostly lower branches) look just fine.

Thanks.
 

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coh

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#2
It could be too much sun. A few years ago I repotted a larch just as the buds were showing green (i.e. the right time). It started growing and I figured it was ready to move out into more sun. I was wrong :( All the new growth browned and died and I lost all the branches that had been developed. Fortunately enough new buds eventually sprouted from the bases of the branches and the trunk and the tree is doing well now, but I lost many years of branch development.

I've read that some suggest not putting larches back into a sunnier spot until you see evidence of strong extension growth. Others have said they should be sheltered from excessive sun the whole season after a repot. I don't know exactly where the truth lies but it all suggests...be careful with the sun at least for a while longer.
 
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#3
Sucks for your developped larch, but at least it made it through. Mine is very immature, so it should pull through, worst comes to worst I can cut back to one of the lower branches, which is the plan anyways in a few years.

So it's weird, larches are quite finnicky with the sun when putting out fresh growth, especially for a species that can't tolerate the shade in nature.

I wonder if the fact that I sheltered it as the buds were opening didn't create overly sensitive needles. Maybe the new growth needs to be exposed to its normal dose of sunlight right away. The sun is absolutely not scorching here in any degree here, especially in May.
 

coh

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#4
I don't think established (as in, not recently repotted) larches are finicky with the sun. I have 5 larches in my collection. Three were repotted this spring and are all in partial sun, so far without any problems. The other two, which were not repotted, have been in full sun all spring and they are fine. We're not too much further south than you. Weather the last few weeks has been mild (normal to slightly above normal temps) and dry with a fair amount of sun. I generally keep my larches in full sun all season if they haven't been repotted.

As for the one I had trouble with, I had purchased it a year or two prior so at least I didn't spend all that time developing those branches! It was a fairly cheap ($40 ish) piece of stock that still needed a lot of work, but some of the existing branches did have a lot of character and age. Such is bonsai!

Good luck with your tree.

Chris
 
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#6
Alright, thank for the advice guys. Those weeks were quite dry, so a wind + sun + dryness + tender shoots explanation makes sense.

I already moved the tree back to a spot with fewer hours of direct sunlight (only AM sun) and I will mist the tree 1-2 daily when there is significant wind. Hopefully it doesn't derail its growing season too much.
 
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#7
Alright, thank for the advice guys. Those weeks were quite dry, so a wind + sun + dryness + tender shoots explanation makes sense.

I already moved the tree back to a spot with fewer hours of direct sunlight (only AM sun) and I will mist the tree 1-2 daily when there is significant wind. Hopefully it doesn't derail its growing season too much.
Did the tree pull through? Did the needles all fall off? I have one with a similar problem.
 
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#8
It could be too much sun. A few years ago I repotted a larch just as the buds were showing green (i.e. the right time). It started growing and I figured it was ready to move out into more sun. I was wrong :( All the new growth browned and died and I lost all the branches that had been developed. Fortunately enough new buds eventually sprouted from the bases of the branches and the trunk and the tree is doing well now, but I lost many years of branch development.

I've read that some suggest not putting larches back into a sunnier spot until you see evidence of strong extension growth. Others have said they should be sheltered from excessive sun the whole season after a repot. I don't know exactly where the truth lies but it all suggests...be careful with the sun at least for a while longer.
How long did it take for the new buds to pop? And is there a way to encourage dormant buds to pop?

I have one with a similar problem that just suddenly dried out and is losing all its needles. I’m hoping with frequent watering it’ll pull through.
 

coh

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#9
How long did it take for the new buds to pop? And is there a way to encourage dormant buds to pop?

I have one with a similar problem that just suddenly dried out and is losing all its needles. I’m hoping with frequent watering it’ll pull through.
Sorry, I don't remember (it was several years ago). Wasn't too long, though...maybe a couple of weeks?

Don't over-water if it has no needles, it won't be using much water.

Good luck. Sounds like you have a difficult environment for larch.
 
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#10
I have had the same issue Adamantium. I did a repot in the middle of summer, nearly killed it. A few weeks later it was popping buds again.
Like coh said, go easy on the water.

I don't know if it's blasphemous or heretic to check the root tips somewhere in the pot, but as long as they're white, it will likely bounce back.
 
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#11
I have had the same issue Adamantium. I did a repot in the middle of summer, nearly killed it. A few weeks later it was popping buds again.
Like coh said, go easy on the water.

I don't know if it's blasphemous or heretic to check the root tips somewhere in the pot, but as long as they're white, it will likely bounce back.
It was repotted this spring, and it’s wired in, so I’d be nervous trying to pull it out of its pot. I guess I’ll just have to hope for the best.

In your case, did all the needles fall off before it budded back?
 
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#12
Sorry, I don't remember (it was several years ago). Wasn't too long, though...maybe a couple of weeks?

Don't over-water if it has no needles, it won't be using much water.

Good luck. Sounds like you have a difficult environment for larch.
Evidently so. I’m just going to hope for the best, and keep things moist. Thanks for the insight, coh.
 
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#13
Just for the record, my little larch didn't make it. It just did not recover from the needles drying up like that.

I feel like I have been unlucky, but next time it will spend more time sheltered from the wind when the needles are coming out after rootwork.
 
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#14
Just for the record, my little larch didn't make it. It just did not recover from the needles drying up like that.

I feel like I have been unlucky, but next time it will spend more time sheltered from the wind when the needles are coming out after rootwork.
Damn :( Thanks for the update.

I’m really bummed. I just got this tree, and thought it was really cool.
 
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#15
Damn :( Thanks for the update.

I’m really bummed. I just got this tree, and thought it was really cool.
Good luck with yours.

I feel like this piece of knowledge about fresh needles being sensititive to dry conditions should be discussed more. I thought larches were bulletproof, but that seems to be their Achilles' heel.
 
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#16
Good luck with yours.

I feel like this piece of knowledge about fresh needles being sensititive to dry conditions should be discussed more. I thought larches were bulletproof, but that seems to be their Achilles' heel.
Same! I wish I'd known before I put mine into full sun. It seems my zone is just a bit too hot. It was doing so well for a while, though!

I got it from a right across the sate in Buffalo, which isn't dramatically cooler, so I am surprised.
 

coh

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#17
I don't know if it's been similar in Montreal, but our summer here has been very hot and sunny with some windy/low humidity days. We started off July with 3 95 deg days and 1 96 deg day with full sun. That's tough on a larch to begin with, if you add in a potentially weaker root system due to spring repotting - you can easily stress the tree badly. I had to move my 3 repotted larches into a dappled sun location when they started showing sunburn (they had looked great up till that point). Even the 2 that weren't repotted were moved to an area that gets shade after about 1 pm.

Good luck with them!
 
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Location
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#18
I don't know if it's been similar in Montreal, but our summer here has been very hot and sunny with some windy/low humidity days. We started off July with 3 95 deg days and 1 96 deg day with full sun. That's tough on a larch to begin with, if you add in a potentially weaker root system due to spring repotting - you can easily stress the tree badly. I had to move my 3 repotted larches into a dappled sun location when they started showing sunburn (they had looked great up till that point). Even the 2 that weren't repotted were moved to an area that gets shade after about 1 pm.

Good luck with them!
Well, the month of May was an outlier, in that we barely had any rain, most days were very sunny and drier than usual. My trees grow on my SE facing balcony, exposed to constant wind from the west side, so I think it might have been sort of the perfect storm for that repotted larch. It was pretty much dead by mid-June.

Trees in the neighbourhood are starting to really be thirsty, we've barely had any rain since June. That includes a few old larches growing nearby. We've had the same heatwave as you guys to start July off (7 consecutive days of 90+ F weather).
 
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#19
It was repotted this spring, and it’s wired in, so I’d be nervous trying to pull it out of its pot. I guess I’ll just have to hope for the best.

In your case, did all the needles fall off before it budded back?
That was two years ago, but if I remember correctly, it wasn't long after they dropped that buds appeared. Half of the needles were still there, but brown and dead when new buds appeared.
 
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#20
That was two years ago, but if I remember correctly, it wasn't long after they dropped that buds appeared. Half of the needles were still there, but brown and dead when new buds appeared.
🤞 I really hope some buds start popping. Thanks, Wires.

I’ll put it into a bit more shade and make sure it never dries out.
 

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