“a composted product that contains beneficial fungus known as mycorrhizae”<<<
This is something that I have no knowledge of, first thought was of mushrooms.....
Looking at google shows links to the product and information.
Garden Girl is in your part of the country, LOL, I forget if it is North or South Carolina she gardens in.
MaxMax knows composts and Diana will also.
Thank you for bringing up a subject we have not talked about and it looks interesting.
Both Diana and Garden Girl work in nurseries, so they may know if others have tried it.