Can you believe – I just found a pile of these clay pipes in my bushcare-site out the back. They are on a sandstone shelf behind the back fence of a house about 4 doors down – covered in leaf litter and weeds. I am assuming, maybe immorally, that no one wants them !? I bring them home one at a time, when dog-walking past, and paint them with black-enamel oil-paint. Then I fill them with potting mix and add a plant as you have shown. (My reward for doing bushcare I suppose).
Some additional examples:
The orchid is Dendrobium delicatum and receives dappled light and a bit of full sun. I just filled the pipe, which is a larger diameter than normally found, with course orchid potting mix. After it settled I placed a few ‘aerials’ that have a good roots system taken from the many clumps of orchids I have growing. To tell if they have growing roots look for the green tip of the roots. Over time the orchids have grown to fill the pipe and expand their root system to the outside of the pot (see photo). A great fragrant and hardy native orchid. I water minimally and fertilise occasionally in spring and autumn.