Native Americans kindly showed the settlers the concept of Three Sisters: corn, squash and beans planted together in the same hillock with a fish at the bottom for nutrients. The corn stalk would grow tall, giving the beans a place to climb. The beans would fix nitrogen into the soil. The squash planted around the base would shade the roots with their big leaves and help to retain moisture. This practice created a symbiotic arrangement that produced a healthy environment for all three plants to survive.