Q: My parents have received contradictory advice regarding their trees’ roots and their septic lines. One contractor insists that they must have the trees cut down and another man said that they should trim back the branches and the roots will stop spreading. Please advise.
A: Well, it all depends on how close the tree is to the septic field. If it is way down at the end of the leach field, there will likely be no problem. That’s the driest end of the field and roots have little temptation to come crawling into the lines. If it is within twenty feet of the beginning of the field, where the lines come out of the tank, I’d remove it. Cutting back the branches won’t necessarily keep the roots short.
If the trees have to go, you can replace them with shallow-rooted, less aggressive plants. Even a dogwood, redbud or flowering crabapple could be considered. Shrubs like anise, Virginia sweetspire, yaupon holly and loropetalum could be planted on the outer edges of the leach field. I wouldn’t worry at all about annual and perennial flowers or bulbs.
An option you might consider is inserting a root barrier between a tree and the septic line. Use a motorized trencher to dig a thin trench eighteen inches deep and insert aluminum flashing on edge into it. The aluminum will prevent roots from encroaching.