Prior to European settlement the area would have borne tallgrass prairie, with groves of trees growing where the lakes blocked some of the advancing wildfires. Today the park is primarily forested with basswood, bur oak, and green ash with a few stands of northern red oak. Ironwood is abundant in the shrub layer and the understory is characterized by Virginia waterleaf. Other wildflowers include nodding trillium, large-flowered bellwort, Dutchman's breeches, bloodroot, jack-in-the-pulpit, and starry false Solomon seal. There are of this habitat type, all of it secondary forest.