Purple Needlegrass (Nassella pulchra)

(Note: legislation was signed by Gov. Schwarzenegger Aug.23, 2004 recognizing purple needlegrass as the official State Grass of California.)

As promised (or threatened, depending on your viewpoint), I am continuing our exploration of some of the wonderful native grasses that can be found on the San Francisco Peninsula. Today’s subject is the most widespread and common of our native perennial bunchgrasses, purple needlegrass, which has a very good chance of becoming our state grass.

Purple needlegrass is a prominent component of numerous plant associations including chaparral, coastal scrub, and foothill woodlands. But the most characteristic image associated with purple needlegrass is the so-called “California prairie” (Barbour and Major 1988), more commonly referred to as valley and foothill grassland (Holland 1986). As described by Sawyer and Keeler-Wolf (1995), stands of purple needlegrass warrant designation as a distinct plant association, which they named the purple needlegrass series. Following their classification scheme, purple needlegrass is also a prominent member of the California oatgrass series, foothill needlegrass series, nodding needlegrass series, and the blue oak woodland series. Purple needlegrass occurs on dry slopes below 5,000 feet in the Coast Ranges from Humboldt to San Diego counties and extending into Baja California, in the Sierra foothills, and on the Channel Islands. I’ll save a discussion of the history of disturbance and threats to California’s native grasslands for another time.

Purple needlegrass belongs to the grass tribe Agrostideae, a large group of grasses that includes such genera as Agrostis, Calamagrostis, Muhlenbergia, Ammophila, Alopecurus, Polypogon, and others. Purple needlegrass was formerly assigned to the genus Stipa, but was reassigned to Nassella upon release of The Jepson Manual (Hickman 1993). Other members of Stipa have been reassigned to the genera Achnatherum and Hesperostipa. Other members of Nassella occurring in San Francisco County include foothill needlegrass (N. lepida) and nodding needlegrass (N. cernua) (Howell, et al. 1958).

Purple needlegrass is a clumping perennial bunchgrass. It is fairly readily detected in the late summer, when the surrounding non-native grasses have died back, by its persistently green foliage. Stands of purple needlegrass will have a hummocky appearance, with clumps looking like mounds dotting a slope. It is most noted for, and its common name is derived from, the long, purplish, twice-bent awns that extend from the tip of each of the flowers that develop from March through May. En masse, the awns give an area a purplish hue.

In San Francisco, purple needlegrass can be found near O’Shaughnessey Boulevard, above the intersection of Palou Avenue and Phelps Street, and on Tank Hill, Twin Peaks, Yerba Buena Island, Bayview Hill, Bernal Hill, Billy Goat Hill, Brooks Park, Corona Heights, Dorothy Erskine Park, Edgehill Mountain, Fairmont Park, Glen Canyon, Kite Hill, McLaren Park, Mt. Davidson, in the Presidio, above Hunters Point Boulevard, and above the Laguna Honda Reservoir.

Purple needlegrass grasslands are not generally afforded much protection from development. As a habitat, it is an “association that is considered rare and worthy of consideration by the California Natural Diversity Database” (CDFG 2003). As such, some local governments, inspired by public comment during review of proposed development projects, will require mitigation for unavoidable impacts to native grasslands. As a matter of course, many biological consultants routinely map distinct stands of native bunchgrasses when conducting surveys of land slated for development as a way of calling attention to the unique biological resources present at a particular site. Whether or not a consultant’s suggestions for avoidance or mitigation are implemented usually depends on the will of the lead agency (county, city, town, etc.) responsible for assuring compliance with the California Environmental Quality Act (CEQA). I’ll share with you a little secret: lead agencies don’t like to upset their constituents. If the public raises issues persistently, the lead agencies can be forced to address those issues in their CEQA documents. This doesn’t necessarily work for every project, but, by attrition, causes an evolution in the thinking of those folks making the decisions regarding how, where, and what gets built. Your actions as concerned citizens have an effect.

The preservation of our native grasslands has increasingly become a cause celebre, earning more and more attention by the public and regulators. As you hike the Bay Area this fall, see if you can spot native grasslands. The more closely you look, you’re sure to enhance both your understanding of and appreciation for this group of plants that, quite literally, holds the earth together.