Do zonal geraniums need to be root bound to bloom? I have a line 6 of plastic tubs, enclosed in a wood frame, on my deck. They are standard rubbermaid tubs, about 15x22 inches. I fill the tubs with annuals every year. This year I want to include geraniums. Is that too big an area for the geraniums to flourish (one in each tub along with filler annuals)? Would it be better to try to contain the roots in a smaller area? They are currently in 4" round pots which I could bury in the tub or simply transplant.