5
Ok, I can finally answer my own question. The reason was that the fabric was closely folded then rolled for the packaging, and when I unrolled the fabric for the permeability test I hadn't seen that I actually poured water on two layers of the fabric stuck together. The permeability is ok with the test on one layer.
I feel kind of stupid. Case closed.
2
The flower indicates that this is a mallow, not as I immediately thought a perennial geranium. So, which mallow? I first thought that the plant was a species of Malva—maybe M. pusilla or M. parviflora, but neither the height nor the flower of these two matched your photo. This is actually a good thing because Malvas are non-natives that are generally ...
1
I did a similar thing using concrete blocks as part of a retaining wall a few years ago. It worked fine once I realized that the blocks absorbed a lot of the water I applied to the plants. Once I switched to plants that tolerated dryer conditions it was lovely and held its own well and the plants grew well. I would recommend using trailing rosemary, ...
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