We have an Acer palmatum 'Sango-kaku' in a container.  It is about 2 
metres tall and is in well drained JI No. 3.  The container is located 
in a quite sheltered place in an area that receives full sun from mid 
morning to early afternoon.

 From Spring until late Summer it looked splendid, not exhibiting any 
signs of problems apart from occasional very minor leaf scorch.  During 
the last few weeks, as the leaves stated to change colour, virtually all 
of them have become very scorched looking and black before falling.

We have not had a great deal in the way of inclement weather in recent 
weeks and it is still quite warm here in S Devon.

Grateful for any thoughts as to probable causes.
-- 
Robert

On 2009-10-31 19:04:14 +0000, robert  said:

> We have an Acer palmatum 'Sango-kaku' in a container.  It is about 2 
> metres tall and is in well drained JI No. 3.  The container is located 
> in a quite sheltered place in an area that receives full sun from mid 
> morning to early afternoon.
> 
>  From Spring until late Summer it looked splendid, not exhibiting any 
> signs of problems apart from occasional very minor leaf scorch.  During 
> the last few weeks, as the leaves stated to change colour, virtually 
> all of them have become very scorched looking and black before falling.
> 
> We have not had a great deal in the way of inclement weather in recent 
> weeks and it is still quite warm here in S Devon.
> 
> Grateful for any thoughts as to probable causes.

Winds? Watering? Drainage?
-- 
Sacha
www.hillhousenursery.com
Shrubs & perennials. Tender & exotics.
South Devon

Sacha wrote:
> On 2009-10-31 19:04:14 +0000, robert  said:
> 
>> We have an Acer palmatum 'Sango-kaku' in a container.  It is about 2
>> metres tall and is in well drained JI No. 3.  The container is located
>> in a quite sheltered place in an area that receives full sun from mid
>> morning to early afternoon.
>>
>>  From Spring until late Summer it looked splendid, not exhibiting any
>> signs of problems apart from occasional very minor leaf scorch. 
>> During the last few weeks, as the leaves stated to change colour,
>> virtually all of them have become very scorched looking and black
>> before falling.
>>
>> We have not had a great deal in the way of inclement weather in recent
>> weeks and it is still quite warm here in S Devon.
>>
>> Grateful for any thoughts as to probable causes.
> 
> Winds? Watering? Drainage?

Not to mention, it's autumn.

You describe a tree in an ideal situation.  Except that it's in a pot.
If you've managed to water regularly, there should be no problem unless
the tree has fallen to verticillium wilt.  This will be recognizable be
black patching and streaking on the branches that starts from the
extremities and works its way towards the main trunks.

Otherwise, that leaves the pot.  When was the last time it was root
pruned and had a change of soil?  Is the tree too big for the pot now,
perhaps some root rot is setting in?  If it's been over 3-4 years, give
it a good prune.  Maybe find a bigger pot if you want more size on the tree.

If none of this matches, and the tree has good looking buds and no black
tip dieback (or not more than normal anyway, SK is notorious), don't
worry it will probably be fine in spring.  Acer palmatum sometimes
doesn't colour for one reason or another, maybe it's just gone dormant
with no display.

HTH

-E

In message , Emery Davis 
 writes
>Sacha wrote:
>> On 2009-10-31 19:04:14 +0000, robert  said:
>>
>>> We have an Acer palmatum 'Sango-kaku' in a container.  It is about 2
>>> metres tall and is in well drained JI No. 3.  The container is located
>>> in a quite sheltered place in an area that receives full sun from mid
>>> morning to early afternoon.
>>>
>>>  From Spring until late Summer it looked splendid, not exhibiting any
>>> signs of problems apart from occasional very minor leaf scorch.
>>> During the last few weeks, as the leaves stated to change colour,
>>> virtually all of them have become very scorched looking and black
>>> before falling.
>>>
>>> We have not had a great deal in the way of inclement weather in recent
>>> weeks and it is still quite warm here in S Devon.
>>>
>>> Grateful for any thoughts as to probable causes.
>>
>> Winds? Watering? Drainage?
>
>Not to mention, it's autumn.
>
>You describe a tree in an ideal situation.  Except that it's in a pot.
>If you've managed to water regularly, there should be no problem unless
>the tree has fallen to verticillium wilt.  This will be recognizable be
>black patching and streaking on the branches that starts from the
>extremities and works its way towards the main trunks.
>
>Otherwise, that leaves the pot.  When was the last time it was root
>pruned and had a change of soil?  Is the tree too big for the pot now,
>perhaps some root rot is setting in?  If it's been over 3-4 years, give
>it a good prune.  Maybe find a bigger pot if you want more size on the tree.
>
>If none of this matches, and the tree has good looking buds and no black
>tip dieback (or not more than normal anyway, SK is notorious), don't
>worry it will probably be fine in spring.  Acer palmatum sometimes
>doesn't colour for one reason or another, maybe it's just gone dormant
>with no display.
>

Emery - many thanks.

No signs of black patches and streaking.  We bought the tree 18 months 
ago and transferred it to its present container, a 17" pot, during March 
this year, so the root situation should be all right.  There are some 
buds evident now but no tip dieback although many of the branches 
exhibited around an inch of dieback in the spring.

I was concerned because the leaves were turning black rather than going 
through the usual gamut of changes prior to falling.

With a bit of luck all will be well next year.

-- 
Robert