Permaculture is the practice of mimicking nature.

Through observation we understand the relationships between soil, plants, the elements and seasons. These understandings become a the backbone in environmentally sound garden design.

Permaculture was created by Bill Mollison in the 1970's. He was inspired by the unifying practices shared by aboriginal societies all around the world. 

Examples of Permaculture are using companion plants that occupy separate niches in an ecosystem, while also working together forming symbiotic relationships, (ie, producing mulch, attracting beneficial birds and insects, creating shade and protection, fixing nitrogen)