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