Santa Fe Botanical Garden

Common name: giant sacaton, big sacaton, zacatón

Family: Poaceae (Grass)

Distribution: Central and Southwestern United States, Mexico

Habitat: Bottomlands, floodplains,moist open hillsides

Hardiness: USDA Zone 5 (-20 to -10 °F)

Life form: Grasses

Occurrence in New Mexico: New Mexico native plant

Growing Conditions: The native range of giant sacaton extends from southern California, Utah and Arizona, east to Oklahoma and Texas, and south to southern Mexico. Overgrazing, agriculture, lowering of watertables by groundwater pumping and erosive channelization has resulted in present growth in only a small fraction of its original range. Because it needs moist soil or access to groundwater, giant sacaton grows mainly on low alluvial flats, bottomlands, arroyos subject to flooding, along riverbanks, or in desert wetlands. In southeastern Arizona and southwestern New Mexico, it forms nearly monotypic stands on broad floodplains. It is prominent along the Rio Grande in Texas. It can also be found on open, unshaded areas such as rocky slopes, clay flats, plateaus, and mesas, if water is available. It grows in full sun and is shade intolerant. It grows on sand, loam, or loamy clay, and is tolerant of saline and calcareous soils. Giant sacaton is important for slowing runoff, enhancing filtration, trapping sediment, and impeding erosion during flash floods in floodplains.

Description: Giant sacaton is a coarse-stemmed bunchgrass that is one of the largest grasses in the region. It can form fountain-like clumps more than 3 feet wide and 6 feet tall. The leaf blades are long (up to 12 inches) and slender, flat or with rolled edges, and with prominent midveins. Leaf sheaths are open, with a few hairs at the collar. The influorescence is a loosly branched, feathery panicle, with secondary branches closely flattened against the primary branches. It is densely flowered with purplish or greenish stalked spikelets that cling to branches of the inflorescence. They do not have awns. This species will survive long-term droughts but will not thrive outside floodplains without irrigation.