I live in zone 5. Long story, I apologize, but I am basically in tears.
1.5 years ago we bought a house with a few patches of Japanese knotweed here and there. Most of it is under control (for now at least) - no large surfacing rhizomes, no large plants, they all get trimmed by hand and immediately treated with glicophyte. Except for one disaster I just discovered.
We have an area around a maple tree, about 12-15 feet in diameter, bordered with rocks. Last year a landscaper put down supposedly landscaping fabric and about 4-5 inches of topsoil. Turns out it was not really landscaping fabric but something that resembles fleece. Effectively we covered knotweed with a warm blanket and gave it some prime nutrients to overwinter. Right now half of that topsoil is riddled with very fine thin roots, and some stalks are coming up.
Extremely angry, not sure what to do now. I am thinking about lifting this fleece up, treating exposed roots, covering everything up with two layers of landscaping fabric, making sure it is all tightly sealed around the edges and seams.
To make the area somewhat attractive since it is in the middle of our small yard, I was thinking of putting down some mulch and setting up plants in containers. My questions: is this an ok plan? Could I do the two layers of landscaping fabric and then put more topsoil and plant what I had originally planned? Or will that be too risky? Am I doomed to container gardening in that area?