Pacific reedgrass (Calamagrostis nutkaensis)

I was reading two excellent articles about native grasslands in the April issue of Bay Nature magazine, when it dawned on me! In nearly 11 years of writing this column, I’ve completely neglected the grasses. I’m a huge fan of our resilient native grasses, and a long-time advocate of the preservation of our remaining native grasslands. I’ve surveyed native grasslands all over the state, and designed and implemented numerous native grassland restoration projects (even in my own yard). How could I have failed to share my enthusiasm for a group of plants that, perhaps even more than the oaks, exemplifies the California landscape? This is the first in a series of articles about some of the San Francisco Peninsula’s native grasses.

The grasses are an oft-maligned group of plants, primarily due to their confusing and tiny floral parts and the consequent difficulty of keying them out, but also because their pollen causes “hay fever” and great springtime suffering by many people (myself included). To many folks, they all look alike. But to others, they are exquisite and sublime. I’ve often wondered why horticulturists insist on importing exotic (and frequently highly invasive) ornamental grasses when California is host to so many equally handsome grasses. I suppose the old adage applies: the grass is always greener…

The typical grasses belong to the family Poaceae. Although their flowers might not look like much, the grasses are indeed flowering plants, belonging to the same Division (Anthophyta) as magnolias and daisies. However, unlike the dicots (Class Dicotyledonae), the grasses are monocots (Class Monocotyledonae), the same Class as lilies, orchids, and irises. The monocots can usually be readily distinguished from dicots by parallel leaf venation and the presence of floral parts in multiples of three. As you might expect, there are exceptions, but this rule holds true for the most part. The monocots are also differentiated by producing only a single seed leaf (cotyledon) and having vascular tissue (phloem and xylem) arranged in bundles scattered throughout the stem instead of in a ring at the stem’s outer edge (such as the cambium in dicots). Did you ever wonder how a palm tree (a monocot) can stay intact in the face of a hurricane’s wind, while the trunk of a woody tree many times greater in diameter snaps like a match stick? Those vascular bundles give the monocot stem extraordinary flexibility and strength.

Worldwide, there are approximately 9,000 species of grasses belonging to some 650 genera. They include the most important agricultural crops known to civilization such as rice, wheat, corn, oats, barley, millet, sorghum, sugar cane, and bamboo. California supports around 580 taxa of grasses belonging to 121 genera. These consist of 364 native taxa and 217 naturalized non-native taxa. Another 80 or so species are used as ornamentals or are cultivated as agricultural crops. Our native grasses range from tiny annuals to robust perennials forming large clumps or vastly spreading colonies. California’s native grasslands have undergone an assault for the past 200 years, suffering from the spread of well-adapted Mediterranean annual grasses, over-grazing, fire suppression, land clearing, and, more recently, development. Many grass species are on the verge of extinction. Currently, there are nine California grass taxa listed by the federal government as endangered and another three listed as threatened. The California Native Plant Society has a total of 19 taxa on its List 1B (rare, threatened, or endangered in California and elsewhere), 26 on its List 2 (rare, threatened, or endangered in California, more common elsewhere), three on its List 3 (need more information), and 15 on its List 4 (watch list of plants of limited distribution).

Not appearing on any list, except perhaps my top-ten list of most beautiful clumping native grasses, is Pacific reedgrass (Calamagrostis nutkaensis). This densely tufted perennial grass grows in clumps up to four feet high. It produces short rhizomes and tends to form dense to sparse colonies. Its clumping growth form can be mistaken for the invasive non-native species tall fescue (Festuca arundinacea) and Harding grass (Phalaris aquatica), which are also common along the coast. But unlike these plants, Pacific reedgrass produces dense, elongate, purplish panicles (flower spikes) up to ten inches long. Leaf blades are flat, about a quarter of an inch wide, and rough to the touch. They form a collar where they join the stem, with a ligule about a tenth of an inch long. Flowering occurs from May through August.

Pacific reedgrass is restricted mostly to moist coastal slopes, meadows, and bogs from Monterey County northward to Alaska. It is often considered dominant enough to warrant classification as its own native community (Sawyer, Keeler-Wolf 1995). It is also a component of California oatgrass (Danthonia californica) grasslands, tufted hairgrass (Deschampsia cespitosa) grasslands, and salal (Gaultheria shallon)-black huckleberry (Vaccinium ovatum) scrub. Pacific reedgrass typically occurs in habitats that are seasonally or permanently saturated with shallow freshwater. It can occasionally be found at inland locations and has been recorded historically from Contra Costa and Alameda counties, although it is presumed to have been extirpated from these counties. It is considered a facultative wetland indicator species (FACW), occurring in wetlands 66-99% of the time.

In San Francisco, Pacific reedgrass was recorded by Howell, et al. (1958) only on the north side of Twin Peaks, near the summit. It can still be found there. Members of the Yerba Buena Chapter of CNPS have also recorded it from Mt. Davidson, Mt. Sutro, Mountain Lake, and O’Shaughnessy Boulevard. In northern San Mateo County, Pacific reedgrass occurs at Sharp Park, and at several locations on San Bruno Mountain, San Pedro Valley County Park, and Montara Mountain. In Marin County, it has been recorded from Sausalito, Mt. Tamalpais, and the Point Reyes Peninsula.

Pacific reedgrass is a unique component of coastal habitats. It is valuable for controlling soil erosion, and is capable of persisting even with the encroachment of eucalyptus and invasive grasses. Nowhere is this more evident than on Mt. Davidson. It has probably escaped overgrazing due to the coarseness of its foliage making it somewhat unpalatable. All things aside, it is very encouraging to come across remnant stands of Pacific reedgrass while hiking on our fabulous coastal slopes. Keep an eye out for this magnificent native species!

Howell, J.T., Raven, P.H., Rubtzoff, P. 1958. A Flora of San Francisco, California. University of San Francisco, San Francisco.
Sawyer, J.O., Keeler-Wolf, T. 1995. A Manual of California Vegetation. California Native Plant Society, Sacramento.