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Thursday - January 14, 2010

From: Hudson, FL
Region: Southeast
Topic: Invasive Plants
Title: Will Arborvitae (Thuja occidentalis) roots cause problems in a leach field?
Answered by: Nan Hampton


A new neighbor is concerned my Arbovitae's root system will go into his leach field. His house has been there also for the same amount of time as the tree and the field. The tree is 45 years old. Do I have to worry?


Well, I think if your house and your neighbor's house with its leach field have been there for the 45 years that your  Thuja occidentalis (arborvitae) has been growing and there hasn't been a problem so far, then there isn't likely to be a problem.  Virginia Cooperative Extension has an article, Planting on Your Septic Drain Field, that gives guidelines about distances for planting trees from leach lines.  The article classifies several trees according to their aggressiveness for invading a drain field.  Unfortunately, arborvitae isn't one of the species listed, but I couldn't find any indication that arborvitae is considered to have particularly invasive roots.  The article recommends a distance of 25 to 60 or 70 feet from the leach field depending on the aggressiveness of the tree.  If your arborvitae is closer than 25 feet to your neighbor's field and he is exceptionally worried about its roots invading, you should suggest that he put in a root barrier (see the Virginia Cooperative Extension article above) between his field and your tree.


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