In article ,
Pam Moore wrote:
For the person who was enquiring about adding microrhiza when
planting, this was featured on "A year at Kew" tonight. A rare tree
was being planted, and microrhiza was added to the planting hole.
David Attenborough was doing the official "planting" bit. He sounded
very breathless; not too healthy at all.

Just because Kew can do something doesn't mean us oiks can. I know
a bit about this area, and it is just a waste of time and money for
amateurs. Mycorrhiza (sic) are SERIOUSLY soil, host and climate
dependent, in general, and the methods of transmission are poorly
understood. Most terrestrial orchids are obligate mycorrhizal
hosts, but UK woody plants are facultative ones, and will grow
perfectly well in reasonable soils without them. They need them
only in poor soils. Yew has none; birch has dozens; in many cases,
it is not always known whether associations are mycorrhizal or
parasitic, or whether plants ever form mycorrhizal associations.


Regards,
Nick Maclaren.