Arch wrote:
I have heard that soluble iron compounds as in fertilizer products used
to correct iron deficiency in ornamental plants will work.

I use that, get it from the plant/nursery store. It is a very fine rusty
red powder, in a plastic container. I forget how it is labeled but I
just call it iron powder. It keeps the copper beaches red and is good
for 'burning bushes' too. (no I'm not making a joke) And those red
maples. Chelated iron, that's it, I remember now.

John