The Blue Ridge Parkway is unique in that it covers a wide range of habitats along the north-south axis of the Appalachian Mountains, such that the flora on a mountain summit at the northern end of the park may be quite different from the flora of a mountain summit at the southern end. Some of these habitats are exceptionally rare in the region and a few are even globally rare. An example includes rock outcrops at high elevations, which contain a fragile group of alpine species that were pushed southward during glacial times and eventually were left stranded on the southern mountains. The main threat to this fragile plant community is trampling by unaware park visitors. Another unique habitat is the Grassy Balds which were likely grazed by native animals such as bison and elk, but which now are maintained by park biologists.
The same environmental variability that leads to such spectacular bloom displays in the spring and summer also contributes to autumn leaf color. The first leaves to change are those of deciduous trees on the highest elevations, which change to vivid shades of orange, red, yellow, and purple. Throughout the month of October the leaf color changes gradually, beginning in the high mountains and concluding at the lower slopes and valleys.