Short grass and mixed grass prairie communities cover the park’s uplands. Vegetation composition consists of species tolerant of clay and sandy soils and drought. The dominant grassland species in clay soils include blue grama, needle-and-thread grass, western wheatgrass, buffalo grass and thread leaf sedge.
On sandy soils, prairie sand reed grass, sand and little bluestem, sandhill muhly, sand drops reed and Indian rice grass are the dominant species. Some shrub invasion of grasslands has occurred by sand sagebrush, yucca and prickly-pear cactus.
Diverse wetland, riparian and aquatic plant communities have become established around the reservoir, below the dam and on large seeps that exist below distribution canals. One rare plant species, the showy prairie gentian, is known to occur in the park.