I planted a self raised cutting from my original "Hot Lips" plant in the new garden I am creating. The soil in this garden is good and friable and this year we had cooler temperatures and a lot more rain than normal. The plant grew and grew ( as did almost everything else I planted), the flowers were prolific and......all bi-coloured whereas the mother plant, coping with heavier soil and, in normal years no irrigation,is still much smaller and producing far fewer flowers that often are all red or all white. So, perhaps the answer does lie in the soil and/or weather conditions although I always consider Salvias to be pretty tough characters on the whole. Obviously I have no idea whether the cutting came from a branch with white flowers, red flowers or bicolored ones but I would not think it likely that one could produce a single coloured plant by this method of selection although it would be an interesting experiment.