Bunchgrass Basics; Simplifying California Native Bunchgrasses

by Judith Larner Lowry

Welcome to the wonderful world of California's native bunchgrasses. They’re an intriguing, varied, and beautiful group, drought-tolerant, important for wildlife, providing good forage for livestock, erosion-resisting with their deep and wide fibrous rootsystems, and uniquely Californian.

They are also severely decreased in numbers. There are two ways (at least) to use native grasses: First, in large-scale grassland restoration projects or pasture recovery programs, and second, as design elements in landscaping projects, which can include "mini-prairies" in small groupings, or as accent plants. Let's see more mini-prairies!

There is much, much to say on prairie/grassland restoration, which can be of interest to the gardener as well. In fact, it may become a fascination (or obsession (speaking from experience).

For a variety of reasons, the perennial grasslands of California have largely (some say 98%) been replaced by annual grasses from elsewhere. This change has had a huge impact on our ecosystems. Restoring the original perennial native grasses in rangeland results in less erosion, the maintenance of long-lived mycorrhizal connections, which can in turn foster a greater diversity of forbs, and longer periods of higher quality nutrition for livestock.

One example of the difference in function between annual and perennial grasslands is the difference in rootsystems. Annual grasses can easily be tugged out of the ground, and add little biomass to the soil, while perennials have large fibrous rootsystems going sometimes 15' into the soil, and would definitely require a shovel to remove.

Another telling example of the consequences of the differences between annuals and perennials in a grassland is the different consequences of fire. It can be good for bunchgrasses, cleaning out old stalks to make way for new and for making nutrients available to the long-lived root-systems. The gardener can take the place of fire by pruning after the plants go to seed. In the weedy annual grassland, fire often removes most annual biomass.

The seeds of annual grasses are still present in the soil seedbank, ready to germinate with the next rain. When rain hits the denuded soil, erosion can also follow. Until those seeds sprout and grow,  which is dependent on that year's rainfall, there will be little fodder left for livestock,  cover for other fauna, or protection for the land, and the bare soil provides new opportunities for even more weedy species to move in. 

The gardener who wants to use native grasses on a smaller scale can definitely profit from knowledge of grasslands, if desired. But on a landscape level, they can be treated like other garden plants,  planted out in plugs, 4" pots, or 1-gallon containers, and placed exactly where the design wants them, rather than sowing seed directly in the ground. Using several different species, giving each its own but overlapping area, is one good way to go. If larger grasses, like Pacific reedgrass, Calamagrostis nutkaensis, Deergrass, Muhlenbertia rigens, or California fescue, Festuca californica, are used, they should be placed two to three feet apart, which won't happen if seed is direct sown in the ground. Much seed will be wasted.

Here are responses to some of the most frequently asked questions.

  1. Timing: October through February is a good time to sow native grass seed directly in the ground. You may require supplemental irrigation if the rains stop before the seeds have germinated and made good early root growth. Seeds and seedlings need consistent moisture.
  2. For more control, any time is a good time to grow grasses in 4" pots in a greenhouse or protected place, though fall, winter, and early spring, with the rain, are the easiest. These pots can then be transplanted to the garden, with moisture supplied either naturally in the fall, winter, and early spring or by the gardener the rest of the time. Simply sow a small pinch of seeds in each container, cover with 1/2" of soil, tamp down, and water. Remove all seedlings except one when they have germinated and made early growth. Continue care till roots have almost filled the pot. Then transplant to garden. It is true of any plants, no matter how drought-tolerant they turn out to be, that they will need consistent moisture as they get established in your new native prairie. Once they have gone through a dry season with your help (weekly watering of 1"is the rule of thumb), you can let them turn golden/green in late summer and enjoy their waving seed stalks, or trim them neatly. Every three years or so, we prune most bunchgrasses almost to the ground, simulating grazing, with which they evolved.
  3. What to Plant Where: Which species of grasses should you plant? The wonderful thing about California is that we have so many different ecosystems; the challenging thing about California is that we have so many different ecosystems. It’s difficult for us to know definitively which particular bunchgrasses used to grow or may still grow at your exact particular site, but to make the best guesses possible, we recommend the following.
  4. - Have a knowledgeable grass expert see if you have bunchgrasses already growing on the site, so that you can augment that species through proper mowing or grazing techniques and through removal of invasive species. Use this site for seed collection as well.
    - Next best is to have a nearby site with native bunchgrasses and similar elevation, aspect, and soils, that you can use as a model for your created native prairie..
    - Reference local floras of your area, available through the California Native Plant Society. Use online sites like NRCS Data Sheets and CalFlora for ranges of specific species, county by county.
  5. The single greatest problem growing bunchgrasses is non-native invasive species, particularly alien grasses. Ways to knock them back are addressed in our “Notes on Natives” series, in chapbooks called Notes on Growing Wildflowers and Notes on Native Grasses.
  6.  Remember that it is not seeds themselves that prevent erosion and hold the soil, but growing plants with existing root systems. If you have a steep slope, jute netting may be required to prevent seeds being washed downslope.

7. Have realistic expectations.

For more background on the ecology of native bunchgrasses, see our Notes on Native Grasses or the chapter “The Land Wore a Tufted Mantle” in Judith Lowry’s Gardening with a Wild Heart.

    There is much to say on topics of grasselands and on grazing, and understanding this ecosystem is helpful for the gardener, but not essential, since, as said above, they can be grown like other native garden plants, ie, from containers.

    Container growing rather than direct sowing: We grow seedlings in pots throughout the season, but ideal planning for growing your own plants in pots is to sow three to six months before you want to put them in the ground. Though restorationists frequently use plugs and liners (long narrow containers), and they may be required for large areas, we prefer growing them the horticultural way: seeding directly into 4" pots, and when they are sturdy little plants, into the ground. Our thinking is that since they are not tap-rooted but fibrous-rooted (one of their main advantages as far as deep erosion control is concerned) square 4" pots suit them, and so far our experiences have borne this out. The very deep and narrow pots are often used for restoration situatiions where additional water is not available.

    Remember that the indigenous peoples of California also used native grass seeds for pinole, roasted ground seed foods. They provided a consistently available source of nutrition. Basketmakers use deergrass for basketry.

     Peggy Rathmann, of Marin Carbon Ranch, is one of many ranchers who now understand that raising cattle is about raising grass, the kind that is available through the seasons. Research at the Ranch shows, among other discoveries, that spreading a thin layer of compost over perennial grasslands increases their ability to sequester massive amounts of carbon. As Peggy said about restoring native grasses:

    “It can take a while. But it’s so worth it.”