QuestionI purchased and planted this tree in a planter box because I know there were limits to it's growth in height over many years. However, it is close to my house and I am wondering about the density and growth pattern of the root system due to underground plumbing in the vicinity?
AnswerThe roots will grow about 1 1/2 the width of the foliage and about 2-3 feet deep. The planter box will confine them from spreading in width. Sealed pipes are not a problem with tree roots--the roots can not get into the pipe. The older type clay sewer pipes are not sealed and can allow the roots to enter if there is a crack. Modern plumbing is not at risk for tree roots. So I would not expect there to be a problem.
