While not having tried this myself I have heard about taking landscape
fabric, spraying it with insulation foam and embedding small rocks and pea
gravel.

Alternately you could use spray foam on the side of the preformed pond and
embed the small stones like a stone wall.

Good luck.

"Rockypierre" wrote in message
om...
How to cover the exposed steep black plastic under the flat rock
border?

One thought is to add piles of large rounded stones on shelves, then
fill the gaps with smaller ones, while planting marginals in the gaps.

Any thoughts?
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