Well the s. flava var. atropurpurea I have have been sitting in the same tub 2 years without a hint of red. tired of waiting, I mixed a batch of tannic tea (Rob Saciloto's recipe) and started watering. 3 weeks worth, in spite of our rain! They have leaves now at 18 inches and threatening to open any day now. I just went out to fawn over my babies, and I see the red tint of atropurp starting! Hopefully this year i will finally see my babies in full splendor! Pics will be forthcoming if they decide to go through with this color tinting! Tannic tea seems to work just fine!