You can also use them as guards at VP locations and gates. It will slow the monsters some. That was my mistake in our first game. I should of just planted them at the highest VP locations since they move so slow. Also, don't clog your streets with them since they will slow down your CAL & INF units.
Thanks for the responses. I feel sorry for them. I'll design a ship to dock at the port and they can board it and get away...yeah...that'll be the ticket...wait...the sea serpent is in the advanced rules. Death on land or death by sea. It truly sucks to be a peasant.