On 12 Mar 2013 23:31:55 GMT, Emery Davis
wrote:

On Tue, 12 Mar 2013 19:07:48 +0000, rbel wrote:

high hedge over) so I am intrigued as to the benefit of applying copper
(sulphate?) to acers in such weather.

The idea is to stave off attack by Pseudomonas syringae bacteria as the
skin goes through freeze/thaw cycles. It's a scourge on most snake
barked (macrantha) species as well as red or yellow barked palmatums.
Pseudomonas also accounts for a lot (maybe most?) twig dieback in maples,
although certainly some dieback comes from wood that doesn't get a chance
to ripen sufficiently in our climate.

Copper (sulphate indeed) is an effective tool against pseudomonas, both
as a curative (but limited) and as a preventative spray.


Many thanks. I have a couple of Sango Kaku that would probably
benefit from a spray of Bordeaux mixture.
--
rbel