the trees were free while the pvc structures cost.
I cringe every time I see the term "PVC". To me, PVC means the white PVC pipe rated for indoor plumbing. That stuff is breathtakingly expensive in any quantity. Don't know if they still make thinwall black polyethylene irrigation pipe, but it's
much cheaper. It comes in rolls, and your trees may come out a little banana shaped. You could turn the curve upward so the trees come out more perky looking. It should be much more affordable than PVC. The trunks may still have to be PVC, as I don't know if you can get 4" polyethylene irrigation pipe.
