The Shawnee Hills Collection forms much of The Arboretum’s southern extension and borders the Pennyrile and Mississippi Embayment regions, just as it does naturally.  A great deal of new exhibits have been added to this interesting region over the past several years, including over 20 tons of sandstone boulders and a 4 acre wildflower meadow, both installed in 2014.  Additionally, the Shawnee Hills Floodplain Forest exhibit includes a boardwalk though a seasonally flooded grove of willow oaks.  The understory is planted heavily in ferns and wildflowers such as milkweed, bluestar, iris (4 species), and lobelia (3 species).  Most impressively, the Shawnee Hills Ephemeral Bed was created close to 10 years ago and in that time the wild-collected wildflowers (various trilliums, trout lilies, shooting star, ginger, bellwort, Jacobs ladder, bluebells, and many others) have spread around nicely, and in spring it is a must-see.

The trees of the Shawnee Hills encompass both upland sites (where cherrybark oak, shagbark hickory, bur oak, American elm, butternut, and hawthorn dominate) and lowland sites (bald cypress, poplar, black willow, sweetgum, willow oak, pin oak, green ash).  Interesting shrubs are plentiful in this region as well, notably, American snowbell, farkleberry, bladdernut, strawberry bush, and false indigo.

From ‘The Big Picture: Ecological Regions of Kentucky’ by Dr. Julian Campbell:

 “The Shawnee Hills form the region generally known in Kentucky as the Western Coal Field.  They also extend into much of southern Indiana and Illinois, where they were named for the Shawnee who were probably driven into refuges here after the first waves of settlement in the upper Ohio Valley.

The underlying bedrock is mostly of the same Pennsylvanian age (290-330 million years old) and upper Mississippian age as the Appalachian Plateaus (Eastern Coal Fields), with sandstone, shale and coal.  At one time, this bedrock presumably covered all south-central Kentucky, but eons of erosion have removed all direct connection between the two remaining ‘coal fields’, exposing the underlying Mississippian rocks.

Unlike the relatively rugged Appalachian Plateaus, this region mostly consists of low hills and broad bottomlands.  Much land is more or less poorly drained.  Another difference from Appalachia is that the soils contain a large amount of loess (dust blown eat from river valleys dried up during glacial eras), and this material appears to have increased the fertility of upland soils.  Also, the bedrock contains some thin layers of limestone.  However, the inland swamps are locally quite acid and infertile, compared to more recent or mixed alluvium downstream.”