wow... how interesting!!! Thanks to all who've offered opinions on this. I too am looking at redoing/creating some flower beds.... edging.
I had bought a roll of the "contractors" plastic edging a couple years ago. What a pain to install in an existing yard/bed. If you do it by hand... like I did... it's hard to install evenly. I had to TRENCH around the outside of my rose garden with a small hand trowel (think... DAYS of work)... then try and lay this stuff in there without it popping back out. Never really worked right.
I tried using treated railroad ties... bad idea.... termites. Trashed those...
Meanwhile, a neighbor spent a couple days building forms, trenched out one area of his edging... set the forms in there level.... then mixed up some concrete and poured himself edging. He did his whole yard, driveway, flower beds, by the house... all of it in about 2 weeks.
What he did... was pour a 'crete edging that included a mower strip on the grass-side. He has St. Augustine grass... so he was concerned with the grass running up and over the top of his edging material. With the mow strip... the wheels of his mower ride on the strip while the blade cuts all the way to the edge of the lawn. Then he cleans up with a string wacker.
I tried the 'no edging' method of things. But the St. Augustine grass will grow right into the beds in two weeks. It's amazing really. That grass will grow towards fertilizer... so it loves the flower beds... even if I fertilize the heck out of the lawn.
I'm getting ready to re 'bone' my rose garden... and am considering pouring my own concrete edging and using brick for the pathways. I'm just concerned that the rain water/runoff will leach off the concrete and make my rose soil too alkaline.