Gerrit Hiddink wrote in message ...
Hi,

I have a 17 year old "root over rock" elm (I own it now for 1.5 yr)
that is showing some problems recently: the leaves become yellow
(first some stains, then progressively yellow until they fall off).
snip

In addition to Jim's excellent advice, take the tree (or a list of its
symptoms) to your local bonsai nursery/club and ask the advice of experts to
your *local* environment.

And get a Ficus to take on holidays! :+)
Cheers,
Heidi Aussie