Acer problem

I'm beginning to wonder if there is something troubling Acers and hydrangeas - keep hearing reports of this kind of thing, starts out as a brown area which then spreads and the leaf and stem dies back. Funnily enough, it reminds me of the horse chestnut blotch problem - it starts at the same time of year. Might be worth visiting the RHS site to see if there's any info on there about new problems with Acers
Thinking about it, further to your PM to me, maybe you should look for honey fungus - wait till the autumn and keep an eye on the area for a collection of honey coloured toadstools - if you see them, dig around and if you find black bootlace like threads everywhere, it will be honey fungus. Not that there's much you can do about it anyway.

The RHS has the following to say...
Leaf scorch is caused whenever water is lost from the leaves faster than the roots can take it up. A wide range of environmental factors causes this such as frost, drought, drying winds, hot sun and even salt-laden winds in coastal areas. Foliage will turn brown particularly around the margins and veins, then curl and shrivel. Sometimes symptoms are not visible until later in the season. Scorch does not usually kill; plants showing symptoms should be thoroughly watered and sheltered if possible.

I would suspect that the tree got stressed when we all had that very hot weather - it is amazing how quickly this can happen!

Strangely enough the branches don't all die back and indeed last year some of them started to sprout new growth and leaves - until the frosts of autumn stopped them of course! I hadn't thought of the RHS either - thanks for that - I am a member ...very good for the discount at the local garden centres too!!!! I also had a couple of 20+ year old silver birches that seemed to do the same sort of thing - but which succumbed completely and I have had taken down. They were at the very opposite end of my garden however and all the other trees and acers in the garden are fine. Most odd!

Now then - I do believe you are both correct re the RHS take on this problem as of course although the door to the "garden room" is always wide open - it can still get mighty hot in there on occasion and I have to water the whole lot every day. That BBQ summer ..LOL...fortnight we had ...could have done the damage again this year and certainly the timing is right... now I come to think about it.
Thank you both...I think you may have hit the nail on the head!

Can you explain your term 'garden room' please

OOPS ! Yes - I have been rather vague about that haven't I!! It is actually known as my "sitootery" ....now that WILL have you puzzled...but you can guess no doubt ....it is where you "sit out"...simple - yes?!
It was originally meant to be a conservatory ...but that was far too formal for me. I wanted a semi working area that I could also entertain in. It has gravel on the floor and a large raised bed area full of plants and the acer in the middle! The walls are white and I have about 15 hanging baskets all round it and too many troughs and containers to count! It keeps me busy and like all arthritic OAP's I find it easier to manage than big herbaceous borders nowadays! My guests love it and I can walk out into it from my kitchen with my cuppa and my crossword (oh and my dogs!)at crack of dawn...before the world wakens up.
I will try to put a pic. on sometime when I find out how!!

So it has a roof? If so i is no wonder that your acer has problems... It is getting over heated!

Yes - that is quite possible as it has grown a bit since it was first planted and did beautifully without turning a leaf (!) in the first years! Now it is nearer the double perspex roof I suppose - although I do have blinds throughout which I employ when it is grillingly hot....which doesn't happen that often!!

But an acer needs to grow outdoors!

It WAS outdoors until the roof went on!!!
And it beautifully initially as I said.
I also have acers as bonsai..indoors!

Um... I really don't want to start a disagreement but acers (other than bonsi) really don't do well as any sort of house plant!

Alzheimer, your acer bonsai NEED to be put outdoors. Indoors is the totally wrong environment for these trees. Growing them indoors promotes weak sappy growth and long internodes (leggy growth with big spaces between branches). On top of that acers NEED a cold season. You can protect them from heavy frosts.

OMG...I can see I have inadvertently raised some hackles...which was never my intention. First of all - let me assure you that of course my acer bonsai is outdoors most of the year and only comes indoors when it needs root protection as we get quite severe temps. in this neck of the woods...like minus 6 for weeks on end last winter!!
I can assure you it is not being treated as a "house plant" - perish the thought!
As for the big acer in the garden room - as I said - it was there long before the roof went on and has done very well until last year. I think I may have mislead some of you into believing this sitootery is an all year round heated area ...no way! Most mornings in the winter it was definitely sub-zero in there and so the acer enjoyed its "cold season" as required...same as all my acers in the garden - which have survived very well without any protection from our severe frosts for the past 30 years or so!
I am sure your original estimation of the problem was correct - and the RHS info that you quoted was the correct diagnosis. I will see to it that the seep hose currently laid round the raised bed - and attached to the rain barrel outside - is re-routed to the acer's better advantage!! I will also need to keep the special blind drawn in that area - to cut down transpiration.
I suspect however, that although it is otherwise a magnificent specimen - especially earlier in the year with the primrose/polyanthus and bulb show - it will have to be moved to the real world outdoors - a massive task but becoming increasingly necessary as it continues to thrive otherwise!!
I thank you all for all your concern and advice.

Good luck with moving your acer...

Thank you, Moon grower. No doubt you can also tell me when the best time would be to do so - according to your calendar.....

I try to remember to check for you