Afraid I cannot offer any real advice Ella other than these remedies I culled from the internet.
Make a dry repellent. Working in a well ventilated area, mix 2 cups of sulphur, 1 cup of moth ball flakes and ½ cup crushed red pepper. Sprinkle this in a thick line around the perimeter of your yard, garden, outbuildings and home. Replace every 30 days or following wet weather.
Mix a liquid repellent as an alternative by combining 4 cups of ammonia with 1 cup of lemon scented dish soap. Sprinkle around any area where you want to keep the snakes away. Reapply every two weeks or after a hard rain.
Punch holes in the sides of a coffee can. Fill the can with mothballs and cinnamon capsules and place anywhere you want snakes to avoid. This is a reasonable option if you have outside pets or small children and are concerned about exposing them to naphthalene (moth balls).
Now if you could just manage to find out how St. Patrick did it???