Enhance garden wall without drilling (cladding)

If you also want noise protection, there is the so-called Kokowall. Or the Kokowall light. This can be enhanced with various plants (they either grow up on the coconut fiber, or you attach the plants with clips). The wall itself is extremely thin. Therefore, it would have to fit into your gap... We use these for our mother as noise protection for a highway + planting as a "green wall"....

Did the neighbor really fill up to the height of the wall? That would worry me even more in terms of stability.

Regarding the heights, you should check the building regulations (state-dependent), which can usually be found online. Here with us (Lower Saxony), filling up to 1 meter higher is allowed. There is also something about the wall height, but I don't remember it off the top of my head.

However, I would never do something like that without consulting the neighbor.

The neighbor is now standing about 1 meter above my property because he filled up to the top.

Do I understand correctly: this thing is supposed to be a retaining wall, meaning there is still soil behind it, up to about the height where his exterior wall turns red? Then I see you either urgently need to have a friendly conversation with each other or next year the Third World War will break out exactly at that wall. Beyond a certain point, neighbor disputes escalate exponentially.

Today the neighbor filled up to the second last stone at the front of the red wall. About 1 meter high.

Do you think the wall won't hold?
Then I don't need to build at all. It's also freezing today.

Why should we argue about that? I want to clad the wall with a privacy screen, then I will see him even less, which I don't mind at all.

The relationship is not so great right now, yes that's true.
But he builds as he wants, and I have to suffer.
Also, the foundation of the garage in the picture is already on my property and doesn't look nice. (It's at most 30 cm deep in the ground)

Now I understand your post, those are supposed to represent L stones, what did he build there?

Was there still soil on your site at the time of the construction?

Look, Tomtom 79, this is how it looked last year. Yes, it is supposed to be an L-wall, with reinforcement. As already mentioned, the three-tiered foundations are not connected. Only the wall stones are connected. What I don't understand is why he built the foundation in steps and then the stones on top again?