We bought a snake repellent and it has something like diatomaceous earth and clove and cinnaman oils and it really works well. We did the perimeters of my MIL’s yard and she had no snakes in her yard all last summer. We killed about 6 rattlers just outside but they never crossed the line.
We have copperheads in our Georgia yard and used a similar product.
So far so good. Just need to reapply after each rain. Told the neighbors about it so that they can help keep the snakes even farther away.