Location really determines that answer. Weed is a weed much like any other weed and will grow anywhere just like a weed.
Guess some of us are fortunate to live in a farming community (southern USA) where cbd is legal as long as you pay the license fees....where seeds of every kind are planted direct in ground including cannabis. Before legalization, we planted cannabis seeds in corn fields ….just plant and come back when done.
So will cannabis grow on its own? YES we're doing it every year. Some growers who do a little prepping always have the better crops....cotton, beans or corn.....or weeds that we smoke.