QuestionHello. We have a magnolia tree that is still young (has not grown or bloomed since we planted it 4 years ago). I was informed yesterday during a landscape consult, that we planted it in the wrong place. It needs to be closer to the house in our situation. My question is how deep do the roots go? The best place for it to go would just happen to be VERY near if not over the spetic tank. Will the root system interfere with the septic tank? Will the tank interfere with the tree?
Thanks for any help or info.
AnswerYour magnolia has the potential for getting quite large (30-40 ft. ht. & about 20 feet wide - depending on your climate & other factors). Thankfully, the roots are not invasive...actually quite shallow (about 2 feet) and rope-like.
This is bad if you have sidewalk, curb, or lawn, but good if you have a septic system. All-in-all, a good choice for planting near a septic system.
That said, I'd keep it back at a minimum of 10 feet from the lines...not so much to avoid root issues, but because there are things in the septic line that are not good for a tree, in concentration. You can probably get it closer to the septic tank, if needed.
I wouldn't plant a willow or maple anywhere close to my septic tank or leach lines, but just about any other tree I'd be inclined to plant would probably be just fine. There is an online Cooperative Extension Service Bulletin entitled "Planting on your Septic Drain Field" which may be of interest to you, so far as recommendations, etc. are concerned.
Also, there are copper sulfate preparations that can be flushed into your septic system once yearly that will kill any roots that may have found their way in - and these preps do not have any adverse effect on the microbial population in your septic system, nor do they damage the trees. I have a friend who owns/operates an arboretum in IL, and their septic leach field is in a heavily wooded area - they use the CuSO4 treatment yearly, and have had no problems whatsoever with their septic system in 20+ years.
