A friend of mine has been using a hot pepper spray that discourages squirrels. It is sold for squirrels. Her neighbors feed the squirrels and she wants the squirrels to go away so she can enjoy the birds visiting the feeder. Well, evidently it works for cats, too. She doesn't really like cats, but she isn't interested in harming them. Besides, cats are good squirrel chasers. I didn't say good squirrel catchers, just chasers. Anyway, you could ask your garden nursery if there is a hot pepper spray they sell for keeping squirrels away.