I need to edge my borders when the weather improves a little. What, in you experience, is tge best edging? It would need to be quite flexible as some of my borders are curvy. I look forward to reading about your ideas and suggestions.
My personal favourite is natural shaped boulder or rocks. But if you want the minimalistic look, and the levels are quite flat, then metal strip is probably best.
Whatever you do, DON'T use that green plastic 'wavey' edging you can buy in diy shops. It is cheap, but it's also terrible to put down, looks horrible when it is down and falls to pieces in a few months.
I have too many beds to do but have thought that bricks laid short ends to the lawn would enable me to run the mower over easily with tiny edging plants at the border ends or even thyme or other little plants that you can plant in cracks and walk over.
One way is to use brick pavers, long edge to the grass and level or just a fraction below the level of the grass. That way you can run the lawnmower over them with no harm - and no edging to do. Once a year or whenever, I go over the edge between the pavers and the grass with a strimmer just to sharpen it up. In other parts of the garden I use Smooth Edge just because I don't like recutting the edges every year and I found I fell into the temptation every time of enlarging my borders. However I do need to cut the edges of grass every month in those parts. If you use anything higher than the grass you will have to strim the edge at least once a month to keep it tidy looking.
why not try and source some old paving slabs from eBay or gumtree.
if you get 300 x 300 you could use an angle grinder to cut in half and then lay then 300 long 150 deep.
you could probably get them for a couple £ each plus concrete to bed them in.Not much use for curves though i guess