This is Jan from Denmark. This year we have had some extraordinary sunny and hot weather with little to no rain for the last 3 months. I have some shohin acer palmatums sitting on my bench which is facing the southside - that means full sun the whole day. I have not been aware beside the usual fertilizing and daily watering, and suddently the leafedges start curling followed by the whole leaf turning brown, drying out and now falling off completely - that happend to the whole tree.
When i noticed that happening, I placed the trees behind some big trees, so they are partially shaded - what I notice is that some new leafs is popping out here and there (but not on the whole tree), which is significant smaller than the original leaves that were burned - question is how I should care for it for the remaining of the season?
Let it stay in partial shade out of direct sun/wind, water as needed and do not fertilize and then cross my fingers? Have any of you guys been through the same? I am abit afraid that it will not survive
Hey Jan, sounds like it could be sunburn. I’m new too, but I think it’ll survive. Maybe it’s similar to a full defoliation? It makes sense that the new growth isn’t as large and the old growth had time to accumulate energy so I think you’ll be okay I would probably keep it out of full sun so the leaves can get their cuticle.
Thank you for your reply
That was what i figured out, maybe in conjunction with over-fertilization. I will clearly follow your advice and cross my fingers
Hi! Ye pretty crazy summer this. Never thought Japanese maples would have any sun/heat related problems up here in the north. The japanese maple I’ve had in full sun is also drying up, not entirely but still.
The others I placed in morning sun, sunrise to around 12 then shade untill 17 and those have no issues whatsoever.
Living in Sweden so my guess is that your sun is even stronger, place them in partial shade or morning sun and they should bounce back.
Ye, it has indeed been a crazy summer - what i noticed it that the problem is mainly on those shohin Acer Palmatums - the larger Acers I have has only some burned edges. I am thinking about getting some shadecloth 30% maybe, which I have never imagined is necessary in our climate.
The funny thing is though, that when i purchased the trees in Japan last year in Tokyo, they were sitting in full sun, but had no problems what so ever - maybe it is due to the “pollution particles” in Tokyo that acts like shadecloth.
How often were you watering it?
Is that a tricky question?
I do check in the morning, before i leave for work - if needed Ill water - then Ill water around 17.00 when i get home from work.
Haha, perhaps it was, I’m sorry. How about this one; what color were the edges of the leaves before they fell off?
Brown and crispy - are you thinking about the possibility for some kind of pest-attack?
I’m thinking about all possibilities; just being thorough lol. Sounds like sunburn though. I think your plan is a good one
Carl and Alex,
Here is another one - what is your opinion with preventive spraying for pests and/or fungi? You do it on a schedule, or only when you discover something?
For fungi you have to do it preventatively. My understanding is that the fungicides make it so the fungi spores can’t attach to the plant but once they’re there, they’re almost impossible to remove and you’ll have to wait until next year.
As for pests, I think you can do a preventative treatment and treat as you discover something depending on the pest. I saw that mirai added a pest/disease category to the archive so hopefully that’ll help soon because I have these same questions.
I basically just use soap and water when I move the trees to their dormant location and then once in spring when buds are swelling. If I see pests during the growing season I treat it with soap and water as well. Haven’t had any major problems yet.
On my cembra pine I do the same although if (probably when) I see that white web around buds and candles I spray with soap and water, usually this happens a few time every year on cembra pines.
Soap and water works wonders … So far.
If it’s mainly affecting your shohin there may well be a water issue.
@Ryujinmaru your maple definitely has scorched leaves due to heat. They like partly shaded spots rather esp. during very hot and sunny days. Also preferably water it daily, early morning hours. Japanese shouldn’t be so sensitive to evening watering but just in case. I’ve learned this couple seasons ago on both - Jap. Mapple and Red one too. Since I moved them away from south side and they have just few hours of sunshine leaves are nice and don’t dry starting from edges when scortched by dry winds or burned by sun.
It will be fine, don’t worry but not this year I guess
@CoffeeCherry cheers for your reply - I am happy that I ain’t the only one that has fried a maple ye it looks very sad now, but with good nursing, I hope it will bounce back.
Have you any experience with root burn due to “over fertilizing” with pelletized fertilizer (biogold)? because what I could find on google, this could also be a possibility - though i think you are right - the heat has been insane in Denmark this year.
Glad my experience helped
Re fertilizing with anything it is generally sugested to cut down or even skip during summer and again esp. when it’s very hot.
This year is very hot and dry across Europe and we should be careful and rather put our trees somewhere away from sun.
I noticed you were asking also ab prevention from pests. I wouldn’t do this, just read a bit about it and pesticides actually weaken trees a bit. Again it could cause scorching of leaves - this applies to some deciduous trees. If you have no pests just enjoy it without any extra preventing care if I can suggest
You have a good point.
My wife just had a spidermite-infestation in her greenhouse that within 2 weeks has wiped out all her plants - so I guess i am just paranoid that it would happend with my trees aswell
I guess I will just water and let them recover