When I find a mushroom I know to be associated with a certain tree species I have sometime bring them home and throw a cap at my trees, that's as far as my efforts have gone.
Amanita Muscaria does have a very wide range of tree hosts so it might be a good one, read the article above and go for it!
Ha, hope you can understand a bit of French!
The manufacturer claims these five will work for Alder, Arborvitae, Arctostaphylos, Aspen, Basswood, Beech, Birch, Chestnut, Chinquapin, Eucalyptus, Fir, Hazelnut, Hemlock, Hickory, Larch, Linden, Madrone, Oak, Pecan, Pine, Poplar, and Spruce. I follow the manufacturers instructions and I’ve seen my fir and pine respond well.
Hi Im surprised to hear you associate Fly Agaric with Pines! Here in UK they seem to naturally occur in the wild close to or in symbiotic relationship with our native Birch Betula pendula.
I would suggest some of the smaller toadstool species would be more in scale with bonsai,unless you have an ulterior motive for wanting to cultivate Amanita muscari??!!
Scarlet Elf caps- Sarcoscypha species for example might be persuaded to grow on deadwood or perhaps wood chippings?