made 2 more of these today, super easy just split a round into 2 and then split those into 2 again, screw together with 4 3 inch screws and nail any sort of back on it.
I might put chicken wire on them or not, they can be leaned up without losing soil.
on a interesting side note. I got the rounds from my neighbor who had a renter cut down a tree in front of here house to a stump because it would grow 20 ft a year. I think it is empress tree because the leaves are huge. It is easy to work with and has no knots in it even where there was a branch
but it is not the $$$ wood the internet would have you believe, it smells astringent and have huge open grained rings, also no pith
anyway ! just wanted to share