On Tue, 02 Jun 2009 21:08:22 +0100, Chris Hogg wrote:

Never heard of the stuff, and the analysis makes me suspicious that
it's not the same as Sequestrine, especially the colour and the
presence of magnesium sulphate (it wasn't manganese by any chance, was
it? I suspect not, at that concentration). It could simply be a
mixture of iron and magnesium sulphates, both of which are important
in making leaves green (magnesium is a key component of chlorophyll).
It would probably be OK in the short term, but I doubt if it would be
of long term benefit if you were actually on alkaline soil. But as
it's only to offset the effect of hard water applied occasionally, I
guess it will probably be OK. When dissolved in water, it will be
slightly acidic itself, which will help. I wouldn't use it any more
frequently that it says on the packet, or if no instructions, then no
more than once per month.

Yes, it was Magnesium Oxide (MgO). That and the soluble iron seem to
be the only things listed.

Anyway I've done it now. The powder goes a promising deep green when
you add water. They really know how to sell this stuff don't they?

I'll make a point of getting the sequestrene when next in the UK.

Kate-

Thanks for your link. My french is barely passable but from what I
can gather with the help of the dict, they're not talking about doing
anything very drastic other than pinching out the dead spidery flower
heads and removing weak and low branches. I don't know what "au
marcottage" (layering) means but I wonder, is it a type of pruning
which suits rhodies?

BTW, my acid patch, is only approx 3m by 3m. It's bordered by stones
and against a neighbours wall to allow a soil depth of probably
30-40cms against the surrounding gravel path.

In this dry spell it's fighting a bitter pH battle against tap water
which is chalkier than in any area I've ever lived - the kettle needs
kilrok about once a fortnight.