This is great! - very clever, cute game, and fun working out the routes to make sure they're connected... :)
I found I could cheat (I think?) by leaving an extension halfway across a hedge (and plugging a plug in from around the other side!) to reduce the route length, but I can't imagine an easy way to figure out a fool-proof way of stopping that...
A really fun, novel idea, and I can imagine there's a lot of room to expand on your puzzle and physics gameplay logic if you ever turn it into a released game!