R. ponticumA large growing species of rhododendron from central Europe that has a reputation of being invasive. However, here in northern California they grow large, but are not invasive. I think that when they make and drop seed it is too dry here for the seed to germinate. We have large specimens here along the freeway that never get any care, and are lovely. I was told that it is irresponsible to sell this plant, but do not believe it would be a problem here