It's something I'v been thinking about
You take an old back box that's the baffuls have gone and you cut off one end so you have a nice big open tube. The other end you'd have to cut the pipe's off and leave the hole with a piece of metal wire across for drainage.
Then you remove any thing inside it clean it up.
Then either polish the outside or paint it and then in goes the soil/compost than you plant your Flower plant ie Rose into it.
It's then a unusal plant pot for the garden

I've thought about disgarded piece's of Exhaust pipe as well you cut them into different lengths then stand them on their ends so you have like old Church Pipe Organ constructions and weld them together and then use them as a rather different planter for your flower plants.
I don't know if it can be done but if it could be done I'd be very interested to know how much it would cost.