Hello, and many apologies for the delay in returning a response to the inquiry you submitted about the white mulberry tree planted near your drainfield.

I believe that white mulberry has an extensive and agressive horizontal rooting system, rather than a vertical root system. Mulberry seeds do seem to grown in many places because their seeds are dispersed in bird droppings and such, and tend to be a bit aggressive in their growth. https://www.oardc.ohio-state.edu/weedguide/single_weed.php?id=77

You will see that the above guide describes the root system as such:

• Root System:

  White mulberry produces wide-spreading, aggressive roots that are known to clog drains.

What I am trying to find is a source of information that gives better recommendations for how far beyond the very edge of the drainfield it is safe to have woody plants growing that will not cause damage to a drainfield.

You indicated that the tree is planted 25 feet from the drainfield. Would this be 25 feet from the very edge of the drainfield?

If you will allow me to follow up a bit more about this with some colleagues to see if I can get some additional guidance, that would be great. Knowing if this tree is 25 ft. from the drainfield edge will be really helpful. And any other details that you have.

Like you said, the tree is small, and you plan to keep it small, which is good. If you can get back to me with the additional details, then i can check in with some professionals to determine if it would simply be best practice to remove the tree, or not.



Hello again, I haven't been able to find out any further information exactly, but I did find this resources from not-to-far Ontario, that might provide additional information that might suggest that the best thing to do is not to take chances with this tree, and that you may want to remove it, since it is invasive, and the root system is described as such:

"White mulberry have a wide, spreading root system
with both tap and lateral roots. The lateral roots
are often wide close to the root crown, becoming
more fibrous just a few feet away. One study
characterized the roots as being up to 4 m deep
and spreading as wide as 13 m, with the majority of
the lateral roots occurring in the top 30 to 60 cm of
soil. Roots are bright orange."

The full document can be found here:

https://www.ontarioinvasiveplants.ca/wp-content/uploads/2021/01/OIPC_BMP_WhiteMulberry_June032020_WEB-1-J26.pdf