This Coffeeberry (Rhamnus of unknown species, but intended to be californica) languished on my back slope for years. This one was the success story. One or two others died off earlier.
It could be that the roots were stunted right from the pot, or it could be that they grew that way.
(Western Wallflower) was one I tried as well. It didn't self-seed, though I think it bloomed well enough.