Horticulture and the American Bottom

Horticulture began to emerge in the lower Mississippi Valley after about 1500 BC and may have domesticated a different range of plants like gourds and sunflower. Societies in the area before this probably created earth mounds some dated as far back as 3500 BC. Cahokia was an extraordinary culture noted for its mound building, covering 6 square miles with around 120 earthworks.