Leftover Liner Plant Islands - almost free
I have used these for two years now and they are still doing good. Since they are a couple of years old I don't have instruction pics but you can do it.
I cut a liner "donut" as big as I want from some scrape liner. I then take some leftover pond netting and cover the outside of a flower pot the size I want hanging in the water. You will only use the flower pot as a guide for your size. It does not go into the pond. Leaving a generous edge to "glue" to liner cut the netting. Use Great Stuff to attach netting to the underside of the liner. Let dry. As you can see, you do not see the Great stuff and it floats to hold the liner up. By the end of the summer, the plants will hide the black liner anyway, but it is good shade and not too distracting. If I want them to not get to the skimmer, I just use fishing line to attach to my border blocks.
Attempt something large enough that failure is guaranteed....unless God steps in!