Everyone knows mushrooms are good for potions, but you gotta be careful to use the right ones. Some are poisonous, real poisonous, but that’s not the only trouble… you see, mushrooms soak up all the power from the world around them with their fine roots and hold it in their caps.
So if the ground is sick, the mushrooms get sick, too. Old spells can linger in the dirt, and sickness can linger where goblins once were. Trees absorb these things, too, but large trees are much older and wiser and stronger and can null the troublesome toxins away.
We grow our mushrooms here in the caves, cleaned and protected by hard-working folks and a caring guardian spirit. Hopefully ours are full of simple, natural things, untouched by curses.