The Native Grass Thang

Back in the 70’s when I first got bitten--at the beginning of my own “native grass” phase, I was led to believe that native “bunchgrasses” once cobbled the hills of California but because of overgrazing were now quite rare, so I was duly excited when I first met up with a tuft of that quintessential California bunchgrass Nassella (then Stipa) pulchra (purple needlegrass), on a roadcut some scores of miles from home. But it didn’t take long after that to find out how remarkably common needlegrass and various other native grasses still were, and practically in my own backyard at that. In fact, many grasslands, at least in the Coast Ranges of Central California where I do most of my botanizing, are full of native bunchgrasses. When these grasslands are heavily grazed the perennial grasses are kept very low and inconspicuous, but as soon as there is a break in the grazing the native grasses rebound very quickly and, in April and May, come into luxurious “bloom.” Even then, however, they are often so densely intermixed with weedy annual grasses like wild oats, foxtails, ripgut and ryegrass that they are not so immediately obvious as they would have been before the arrival of the “weeds.” 

The way to really get the perennial bunchgrasses to look like their old prehistoric selves is to burn off all the grass in late spring or summer (preferably before the annual weedy species have ripened their seeds). Within a few weeks, or even days, the blackened ground will be freckled with little circlets or tufts of green as the fresh new blades emerge from the fireproof rootcrowns of the bunchgrasses, each spaced roughly equidistant from its neighbors. These spaces are where the smaller annual flowering plants are presumed to have grown, just as the weedy European invaders do now. This may or may not have always been so. Depending on soil fertility, frequency of grazing etc, the spaces may have been occupied by other plants, or not. The more frequent/heavy the grazing or burning, the more opportunity for flowering annuals to occupy the space. Long periods without such disturbance would lead to monopoly by the perennial grasses, as they fill in the interstices with their own lush herbage and thatch.