Beyond the interesting colour spring, summer and fall, I adore the architecture of the tree itself and love it as winter interest. The shape shows itself clearly and it's presently my favourite tree to prune. It is a charming, elegant and yet whimsical tree. I care for several groves at a local estate and can confirm that they do sucker, but much less than Stag Horn or Smooth Sumac. They also need half the water. My question is " If you where to introduce a root barrier with an established plant, how deep would you make it? What materials would you suggest?