This appears to be steel edging. They usually come in various thickness. For example 1/2", 1/4", 3/18", 1/8". The initial cost is more compared to other landscape edging material, however it is perfect material for creating crisp geometry. I use it quiet often on my projects. I also like the weathered look as it age with a garden.

Thanks

You are welcome. Here is a pic. of how I used it.

It's beautiful.

Thank you :)

That is 1/8" steel landscape edging with black paint finish. Landscape suppliers carry it or can get it . Aluminum is also available and easier to handle.

I love the design of the whole back yard. Very classic and low maintenance. I think it is very beautiful.