Hi, here you have some of the painting and building steps for this base, i hope you can find it helpfull or maybe just interesting!
I tried to use only home-made or simple stuff that everyone could have:
Cork for the basic shape,
a blister-sponge for the moss,
old brushes to make grass,
and some little roots found outside.
(and a bit of putty to cover the cork on the top and make it a smoother surface)
I'll have to prepare some more nice bases for my next projects, pls let me know if you are interested in a photo-tutorial!
have a nice day