My wife and I just naturalized our shoreline, and we’re now looking at what can be planted on our septic field and how close to the field we can plant trees. Our septic is on a hill with a 35- to 40-degree incline; ultimately, we need to secure the sandy soil on the hill over the field.—Pam Brennan and Tara Ursulan, Molega Lake, N.S.
Septic experts and arborists typically recommend planting trees at least six metres away, or 15 metres away for trees with particularly thirsty roots: poplar, maple, or willow, for example. (These species are known for aggressively seeking out water reservoirs—including wastewater.)
As for what not to plant on the drainfield, along with trees, avoid anything with a woody stem, says Sara Heger, a researcher and an instructor in the Onsite Sewage Treatment Program in the Water Resources Center at the University of Minnesota. Happily, there are plants native to Nova Scotia that grow in sandy soil and are safe over the septic system (we’ve recommended native wild strawberry and black-eyed Susan before).
That said, the fact that you’re dealing with planting on a hill does make the situation slightly complicated. “There are two challenges,” says Heger. And you probably already know what they are. “One, steep slopes don’t hold water, and two, sandy soils don’t hold water.”
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You don’t want the soil over your septic system to erode. “The best option may be an erosion control blanket, embedded with grass seed, that is watered during establishment,” says Heger. “You don’t need to grow a lawn. A native grass mix will work.”
But you’ll have to find the right mix. “That can be tricky,” admits Alain Belliveau, the Irving Biodiversity Collections Manager at Acadia University’s K.C. Irving Environmental Science Centre. “One of the big challenges we have in promoting native plants is that we don’t yet really have a good grass mix of native species in Nova Scotia.” Buying something like a wild meadow mix, he says, “can be a bit of a trap. Because often what you’ll find will also include species not naturally found in Nova Scotia or even the Maritime provinces. And while they’re not usually invasive for the most part, they can outcompete other plants if you don’t stay on top of them.”
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He recommends researching each component of a native mix if you want to be sure about what you’re putting on your property. Tedious, maybe, but, “it’s like anything else that you buy. You have to do your homework,” he says. The folks at K.C. Irving would welcome a phone call if you have concerns about a specific species. “We’re always happy to answer questions,” says Belliveau. Oh, but they won’t answer your algebra or French grammar questions. You have to do that homework.
Got a question for Cottage Q&A? Send it to answers@cottagelife.com.
This article was originally published in the Early Spring 2026 issue of Cottage Life.
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