Are there any problems with planting a crepe myrtle on a septic tank?
– Jan M., Winder While crepe myrtles are not huge plants with huge root systems, I still would not recommend planting one on top of a septic tank or on top of the drain field of the septic tank. Crepe myrtles are beautiful shrubs and trees, but try and find another place for the plant if at all possible. Below is a link to a publication concerning planting around a septic tank and drain field. The drain field could be rather shallow under the soil surface, around 6 to 12 inches deep. This particular depth is right where most plant roots are located. Since the drain field is going to be a source of nutrients and water for the plants, the plants will grow towards and into the field if the roots are invasive enough. Woody plants would have more substantial, invasive roots. Therefore, I would only plant turfgrass or shallow-rooted herbaceous perennials over the drain field to prevent clogging and damage. The planting of turf or perennials would also avoid the additional costs and labor inv
