It will catch grass, ect. I would use a band and banding tool. Unless you run strictly desert and there are no clearance issues. I definaltly would not use a zip tie. Unless it was the last resort you had.
There are some really good Metal Zip Tie type found at Lowes and Home Depot in the Elect Dept. I carry them for use out on the Trail. Well I had gave a guy a few of them a couple of years ago that occasionally will ride with us, unbeknown to me he used them as bands and they have lasted over two years so far with no problems at all. He did use a Band Tool to get them good and tight on the front two, but the back two he had done first he simply rolled them super tight with a pair of needle nose pliers!!! They are super tough and will not loosen up at all.