PVC Garden "Pots" -- On b organic with michele beschen episode #212, a CSA had lots of unique planting methods that were inexpensive, deer- & weed-proof, AND accessible to someone in a wheelchair. PVC pipe (10’ lengths) cut into 3 equal pieces, secured in the ground with a piece of rebar, and filled it with soil were used to plant all sorts of vegetables and plants, 1 plant per "pot". Each plant took just one cup of water per day to thrive! Here is a similar idea on a DOT government website.
Also on these boards
Smart ~ cut the bottom off a plastic pot to contain invasive plants & bury in the ground; works great for containing plants that tend to spread. This also works good for planting a plant in an area that tends to get filled with roots etc. from other plants. Use a larger pot so that the plant can spread its roots and grow deeper roots, but keeps other tree roots from choking out the one planted.
Cover to keep squirrels & rabbits out of raised vegetable beds. It is made from 1/2" PVC pipe, PVC fittings & chicken wire.
Disney world does this! Lowes sells the 4 to 6" round PVC pipe with holes already drilled. Purchase an end cap, fill with rock, soil, and plant. I will often put these in the center of a very large pot to stabilize, and add amazing height and color to a container that has trailing plants (no end cap or rock needed if you are placing in a container)