Posted: 14/03/2015 at 08:35
Mycorrhizal Fungi comes as a fine powder in a packet and you use it when planting, you just make sure it comes in contact with the roots of the plant. It is a natural fungi I believe which occurs under conifer trees, you don't need to use much per plant (a couple of teaspoons)
You can supposedly overcome the risk of rose sickness if you use this when planting a rose where a rose as already been.
you can use it when planting anything not just for roses.
as for just planting a rose bed, I dug mine up and replanted the roses with other things as in the winter it really does look very boring. But each to their own its your garden your decision.