How far does the root system of a crepe myrtle tree spread? I have an oleander tree now in the 5' planter between my driveway and my neighbor's. My sewer line is about 4-5' away from the oleander, and there is a problem with roots from the oleander intruding into the sewer line. My HOA says I can remove the oleander and replace it with a crepe myrtle, which supposedly does not have as big a root spread. Is that correct?