Hi Aarch,

Welcome to RMG!

I donÂt have any personal experience with planting aspen near any sort of a cistern or sceptic system, but aspen and cottonwood are very shallow rooted trees, they produce a kazillion roots, and the roots seem to actively seek out sources of water, so if your trees are only 15 feet from the cistern I think youÂre gonna have a major problem after a few years when they start to get established. My one neighbor has a (dying) aspen in their front yard, and I have aspen suckers coming up all over my front lawnÂeasily 50 feet away from the neighborÂs treeÂand in this case we both water our lawns a lot, so IÂm not even especially encouraging them to grow toward me. In the back yard my neighbors have cottonwoods, and since I water and the neighbors donÂt, my entire back yard is an unbelievable maze of cottonwood roots. I think about half the roots those trees have are growing into my back yard looking for water! And the cottonwood roots are getting big enough that theyÂre actually moving a couple sections of my privacy fence and also shifting some of the railroad ties I have. They also grow so much on the surface, that there are places where the root actually grows up above the ground in the lawnÂitÂs nasty! Aspen and cottonwoods are both poplars.

Since youÂre high enough that the aspens will probably do ok, if thereÂs somewhere further from the cistern that you can move them, IÂd sure recommend doing that. Once theyÂre established and starting to send up suckers, even if you decide to cut them down or try to get rid of them some other way, the roots will continue to send up suckers into perpetuity! Once they get started, theyÂre virtually impossible to get rid of. And since you have a source of water in the cistern, thatÂs the way theyÂll keep trying to grow. I think you have a nightmare in the making!

Where are you located? In Colorado? Utah? Somewhere else?

WeÂre glad you found RMG,
Skybird

I know that cottonwoods and aspens are both members of the poplar family.
When I was a kid, my folks moved into a house that had 4 cottonless cottonwoods on the lot. They were fully grown trees. About a year after moving in, we had all kinds of problems with our sewer (city service). It was backing up and our water bill was a lot higher than it should have been. The plumber and city inspectors discovered the trees roots had broken into the pipes and were helping themselves to what they wanted. My parents cut down the trees, but the rest of the time we lived there we spent spraying suckers, chopping roots and generally trying to get rid of them.
We moved out of that house about five years after we moved in. All I can say is when they start talking about haunted houses, I think they are talking about places that have poplars. They will haunt you forever.

Billie

Here is a link that might be useful: Poplar Trees

aarch, someone should offer you a glimmer of hope. If your cistern is fairly new and of the seamless plastic type construction, then you should have no leaks and those Aspen roots may not be such a problem. It's only when the roots find moisture from even a small leak, where they then start sending in all their fibrous roots to get to more of it and eventually wreak havoc. I'd probably mow around the cistern to keep suckers from sprouting any closer in any case though.