I'm guessing that you have some holes in the bottom of the white bucket, so I'd suggest you flush a couple of times and leave it alone, let the soil dry out before you water again. Not necessarily all the way but let it dry quite a bit after flushing. Then see what happens. The only solution to excess fert is to flush. People flush too often thinking it's the cure for what ails a plant, but really is only necessary after too much fert is given, like this plant. It might recover so don't give up just yet. Miracle Grow needs to be used carefully.