The native prairie is classified in the Kuchler Vegetation Type as grama/buffalo grass. To date, 147 plant species have been identified in the park. Plant inventory work has been done here since 1973 and approximately 90 % of the plant species have been documented.
Dominant grass species include Blue grama, Buffalo grass, Sand dropseed, Western wheatgrass, and Side-oats grama. Dominant shrub species include Sandbar willow and Sand sage. Dominant tree species along the river include Plains cottonwoods and Peach-leafed willows.
The principle cactus growing in the park is prickly pear, Opuntia polyacantha, also known as starvation cactus.
Throughout the park there is a wide variety of native grasses. Although the area has been over-grazed and invaded by many exotic plant species, native grasses flourish. Dominant grasses include Blue gramma, Western wheatgrass, Buffalo grass, Side-oats grama, Sand dropseed, and Saltgrass.
- August 31, 1846, Report of Lt. J. W. Abert of his Examination of New Mexico - "In the evening I was carried down to the river, and took a bath in the refreshing waters of the Arkansas. This bottom land was now chequered with brilliant masses of color, produced by the groups of plants which were growing in great luxuriance. The golden rod, the purp. Eupatorium, the sunflower, silver marged euphorbia, and the pink cleome, mingled together, clad in their brightest hues; and the sandy plain that skirted the bottom was varied with the golden gourd, cucumes perenius, and a beautiful species of solanae."