I know it's invasive, but i saw this yellow mimosa on my travels through Spain. In the mountain was a beautiful one with a parking next to it. It was gigantic and had lots of runners going up and it was really invading that little bit. But oh boy, what a great soil it had build, it was so loose and brown and rich and damp and forest smelling like, the whole of Spain everywhere i looked was rocky dirt, but the stuff it had build was next level goodness.
I brought it back up north and it survived heavy frosts this winter , it's not picking up as i had hoped, but it's still around. I sure hope it can build soil like the one i saw up there in those mountains one of these days, that would be a life saver. I hope it goes everywhere making that beautiful soil, but i'm still on the fence if it will vbe that succesful as people describe above.