I have 2 pieris which much to my surprise I haven't managed to kill yet! I've even found a place for them in which they are happy and putting out new growth. But here is my problem, Due to using a bad batch of potting mix, I ended up repotting them last year, and noticed that there was no fresh root growth. I put this down to the bad mix and put them into a free draining mix and moved them into another area of the yard, and as I have said they are responding with new growth. however, yesterday, the dog knocked one of the pots over and cracked the pot (They are just in training pots) when I picked the plant up and repotted it I noticed that it still has no sign of root growth. I am concerned and I would really like to not kill these plants. Has anybody got any suggestions on how to encourage root growth?