We grow a bunch of comfrey in our urban homestead food forest. They grow very well in our climate with no watering necessary and with the variety they do not spread by seed or run super far, it stays clumped up where we plant it. It is an excellent source of flowers for the pollinators, makes great green much when chop and dropped to feed the soil, can serve as a rhizome barrier to prevent the spread of other plants and the ducks enjoy snacking on it.