The 19,300 square miles of the Nebraska Sandhills is one of the largest stabilized dune regions in the world. This area is inhabited by a unique combination of plant species. The Sandhills are a meeting ground for plants found in 5 major types of ecosystems including the Western conifer forest, Eastern deciduous forest, Northern boreal forest, the short grass prairie, and the tall grass prairie. There are 720 species (670 native and 50 introduced) of vascular plants that make up what is known as the Sandhills Prairie.
Topography, soil type, and available soil moisture are important factors in determining what plants will be found on a certain locality. The coarse, dry sand of the dune tops are ideal for deep-rooted warm-season grasses including sand bluestem, prairie sandreed, switchgrass, little bluestem, and Indian grass. Dry interdunal valleys are characterized by finer textured sands, which tend to hold water closer to the surface. These areas are dominated with cool-season grasses such as wheatgrass and needleandthread. Although warm-season grasses such as blue grama, big bluestem, and little bluestem are also found in these areas. Forbs or broad-leafed plants are typically perennial in nature and may include milkweeds, sunflowers, purple prairie clover, spurges, penstemons, puccoons, cacti, and members of the daisy, aster, and pea families. Low shrubs may include sand cherry, lead plant, poison ivy, Arkansas rose, soapweed, and wild plum thickets.
Areas, where water is readily available, can be characterized into two types of plant communities–meadow communities and marsh communities. Meadow communities are found in expansive flat areas between dunes and plant species present vary depending on available water. Well watered but not soggy areas where fine sandy soils are intermixed with silt, clay, and organic matter are classified as hay meadows. The plant species in these areas typically form dense sods and the community is so named because of its usefulness in producing hay. Plants include wheatgrass, needleandthread, porcupine grass, Canada wildrye, prairie cord grass, and switch grass, as well as a substantial forb plant community. Shrubby species such as willow and false indigo can be found along the wetter edges. Plant species present are fairly dependent on the type of hay operation employed by the ranch. Ranches that choose to continuously harvest hay each year will have a different plant composition than those ranches which may graze the area in certain years instead of harvesting hay mechanically.
Marsh communities typically are characterized as wetter than hay meadows but are also found in flat areas between dunes. Plant species in these areas vary considerably from locality to locality depending on soil depth, the constancy of water supply, and water quality. These areas are dominated by grass and grass-like plants, including common reedgrass, reed canary grass, prairie cordgrass, cattails, bulrushes, and sedges. Forbs include swamp milkweed, smartweed, and several species of arrowhead.
The dune, hay meadow, and marsh plant communities make up the largest areas across the Sandhills. However, there are two other plant communities that are important to the ecology of the Sandhills–the blowout community, and what is known as go back land. Blowouts are distinct areas across the landscape where the sand actively moves. While most of the area is void of plants, blowout grass, sand muhly, lemon scurf pea, and blowout penstemon are well adapted to these sites. Blowout or Haydens penstemon is endemic to the Sandhills and is classified as endangered. This plant is often one of the first species to establish in newly formed blowouts but is a poor competitor with other plant species. This results in its rarity as it is pushed out of the plant community as the blowout begins to heal. Blowouts have decreased dramatically due to more controlled grazing and a decrease in the occurrence of fire, thus the habitat conducive to the establishment of blowout penstemon has also decreased.
Go back land is classified as land that was farmed, but has been returned to native vegetation. During settlement, pioneers would readily till up dry, flat areas between dunes for planting crops. As farming became less profitable and less common throughout the drier Sandhill regions, these areas were planted back to native species. Today these flat expanses of prairie are characterized by a dominance of little bluestem. Other warm-season grasses are present but in nominal abundance.
Trees are rare across the Sandhills but do occur, particularly around homesteads, near lakes, and along river bottoms. Cottonwood, green ash, boxelder, hackberry, cedar, plum, chokecherry, ponderosa pine, bur oak, paper birch, and American elm can all be found in areas where conditions are favorable to tree growth. Very few species of trees spread out into the drier uplands of the Sandhills, with exception to plum, hackberry, and chokecherry. These trees can form thickets with other shrub species to provide food and cover for many species of wildlife. Eastern red cedar will also spread into the uplands and have become an issue for decreasing the value of grass-dominated rangelands. The mass plantings of this tree for windbreak use across the Sandhills, as well as the decrease in the occurrence of fire has lead to the aggressive spread of Eastern red cedar. The Sandhills Taskforce spends thousands of dollars each year in helping landowners deal with this issue.