The flora represented at Coronado National Memorial is a mix of Chihuahuan desert and Madrean species with Rocky Mountain and Sonoran influences. The park is at the southern end of the Huachuca Mountains, one of the many Sky Island ranges rising above the deserts and grasslands in southern Arizona and northern Sonora.
The low valleys are cloaked in grama grasses and lovegrasses, dotted here and there with fairy duster shrubs, Palmers agave, and velvet mesquite trees. The grasslands are a swath of gold most of the year, but summer rains transform the hills into waves of green. North of the main park road grasses are generally sparse and include native species such as blue grama, sideoats grama, and plains lovegrass. South of the road, where cattle-grazing occurred until 1990, the grasses are much denser and dominated by the non-native Lehmann lovegrass.
In the mid elevations are the open oak woodlands, the encinal. Beneath the wide-spreading trees grow shrubs: silk tassel, sumac, and point-leaf manzanita. Agave, yucca, and sotol spike the rocky hillsides. Vegetation at higher elevations, particularly in the western portion of the park, has significantly changed since the Peak Fire of June 1988 and the Monument Fire of 2011. Areas that were formerly closed-canopy oak woodland, which may have developed as a result of many years of fire suppression, presently are more open with oak, piñon, juniper, and perennial grass species, particularly bunch grasses and sideoats grama. Succulents such as sotol and beargrass are common as well.
At the highest elevations is found a mixed forest of oak, border piñon pine and alligator juniper. In the very highest reaches of the park, near the Miller Canyon Wilderness boundary, Parry's agave and Gambel oak. MontezumaCanyon cuts through the park’s midsection. Carrying water intermittently, it adds a riparian habitat with tall sycamores and tangles of canyon grape vines. The trees and shrubs of the higher elevation oak riparian zones – Arizona white oak, Arizona rosewood, Arizona sycamore, and catclaw acacia – generally form a well-developed gallery. Channels below 5000 ft are mesquite riparian areas dominated by Arizona white oak, desert willow, Emory oak, and mesquite.
It would be misleading, though, to think of the plant communities at the park forming tidy zones. Different soil types and complex terrain, with slopes facing every direction, provide pockets of warmth or moisture. These micro-environments paint a mosaic of plants. Commonly, a cactus or an agave grows on a warm, rocky, south-facing slope, while just across the trail, on the cooler north side, you will find a healthy piñon pine.
Click the link below for an online list of plants in Coronado National Memorial.