Native Grasses

Some gardeners shy away from including grasses in a garden, thinking they may be too large or labor intensive to maintain. But with only two exceptions, all grasses listed here are considered small- or medium-size and few require annual pruning; some need no pruning at all. They do accumulate enough build-up of dry material to be groomed periodically to remain attractive and fire-safe; some are short-lived and are best replaced after a few years.

Mass plantings of grasses have become a popular lawn substitute, but most gardeners find more satisfaction intermingling them among annuals, perennials and shrubs, allowing plenty of space for expanding clumps and arching flower stalks. Like all types of native plants, grasses thrive in conditions similar to those in their natural habitat. Nearly all tend to be somewhat drought tolerant; all are deer resistant; flowers and foliage attract butterflies; seeds feed birds.

Bouteloua spp.—grama grasses. Known from its history on the shortgrass prairies, deep-rooted blue grama, Bouteloua gracilis, continues its presence in a wide range of conditions, adapting easily but requiring irrigation once or twice monthly. Unusual seed heads are a mark of distinction—extending outwards at tops of stems, flag-like. Tight clumps of fine-textured, grayish green foliage often turn purplish after frost before winter dormancy. Grasses may be mowed, beginning at a young age; older clumps may be too tall for mowing with flower spikes up to 15 inches. Side-oats grama, B. curtipendula, is similar but more drought-tolerant and more robust with flower spikes 2-3 ft. tall. Seed heads drape down from one side of stems in summer and fall. All species grow best in full sun and can be cut back in late winter.     

Calamagrostis foliosa—Cape Mendocino reed grass. Gardeners seeking a beautiful and manageable evergreen grass would do well to look no farther than this native of the northern California coast. Only 12 in. high and 18 in. wide, it sends up masses of long-lasting tawny flower stems from arching, bluish green, grassy mounds in spring and summer. Pruning clumps destroys their natural profile but they are improved by vigorously raking out spent blades and flower stems. Nearly any well-drained soil is adequate. Supplemental water is needed at least monthly in coastal gardens, more often inland where grasses also prefer some shade. Divide and replant or replace after a few years when plants falter.

Carex tumulicola—foothill sedge, Berkeley sedge. Unlike most of the Carex grasses native to California that depend on moist conditions, this species is found on dry soil, tolerates periods of drought, but also appreciates occasional waterings. Be forewarned that foothill sedge is often mislabeled in nurseries as Carex divulsa, an invasive species to be avoided. True foothill sedge is  evergreen in mild climates, forms dense, slowly expanding clumps with glossy leaves to 12 in. or more tall, spreading slowly over time. Plant in shade to avoid a bedraggled look. Flowers—brown and largely insignificant—may be trimmed off or left for birds. Several other Carex species can be used in many garden situations: as lawn substitutes, companions in perennial beds, bank stabilizers, and groundcovers in drainage basins or poorly drained soils. Some require occasional shearing after dormancy; others are evergreen.

Deschampsia cespitosa—tufted hair grass. Spring and early summer bring airy clouds of pale flowers a foot or more above foot-tall, deep green tussocks of narrow blades. Many named cultivars offer various hues of flower panicles in shades of green, often with purplish tints before turning golden yellow in autumn. Because natural habitats are moist or wet, this evergreen grass does not tolerate long periods of drought but requires periodic waterings. Plant in nearly any soil in part shade inland away from scorching afternoon summer sun. Trim off faded flower heads in winter but leave foliage intact unless it becomes too tired looking.

Festuca—fescues. Valued for their roles in a variety of landscape applications, native fescues vary considerably from small to medium clumps of ornamentals to free-flowing ground covers to mowed lawn grasses.

• Festuca californica, a local evergreen native, is one of the most adaptable grasses for Sonoma County gardens. Clumps of bluish green, narrow blades stand 2-3 ft. tall with tan flower spikes rising higher after a spurt of spring growth. It creates a stunning effect on partially shaded hillsides with sweeps of blades flowing downward, commonly seen under native oaks. Tolerant of most soils, this native is best planted in full to part shade inland with protection from harsh afternoon sun; less shade is needed in cooler climates but periodic waterings maintain vibrancy. To renew during late summer semi-dormancy, trim off or vigorously rake out spent foliage.
• Festuca idahoensis is low-growing, forming compact tufts 6-12 in. high with bluish to bright green, fine blades and flower stems up to 2 ft. tall. It is more durable and longer lived than the popular exotic Festuca glauca, blue fescue. It can be divided and replanted or replaced after several years. Periodic waterings keep it vibrant.
• Festuca rubra, red fescue, is often planted as a lawn grass for shaded sites. It slowly creeps by underground rhizomes to create a dense turf and may be mixed with other grasses although it has finer textured blades than most. Red fescue can also be planted as a low-maintenance, fast creeping groundcover and left unmowed in loose, lax clumps 4-12 in. high. It is particularly attractive on slopes where mowing is difficult. Of the many cultivars available, all vary in drought tolerance, color, and height. Not all selections produce flower spikes. Most require moderate moisture for overall attractiveness.

Juncus patens—California gray rush, wire grass. Although not a true grass, its evergreen, wiry character endows this perennial with easy-care. Clusters of golden brown seedheads sit near tops of stiff, evergreen, cylindrical stems 2-5 ft. tall. Slowly expanding, grasslike clumps are at home along water features or in a rock garden, in light shade with little moisture, or in full sun with irrigation, even in standing water as it often occurs in nature. Tolerant of a wide range of soils—including heavy clay—wire grass is able to handle long periods of dry conditions. The only maintenance is cleaning out debris that becomes lodged within long-lived congested stems.

Koeleria macrantha—June grass. Bright green, fine-textured June grass is somewhat unique among ornamental grasses for its small, compact, upright, tufted habit about 1 ft. tall and wide. A cool-season grower, its vertical floral spikes appear in June, carrying nearly cylindrical, eye-catching seedheads 1-2 ft. higher; they open green, turn white, then brown. Grasses prefer sandy, well-drained soil and may falter in clay. They take both sun and light shade, are dormant and semi-deciduous in summer unless given regular water, but revive after dry months when rains begin. Its history as a native prairie grass allows it to tolerate mowing and foot traffic.

Leymus condensatus ‘Canyon Prince’—Canyon Prince wild rye. This silvery, bluish green grass was selected from a Channel Island species known for its spread into wide colonies. ‘Canyon Prince’ expands more slowly than its parent but must be controlled by frequent removal of creeping, shallow rhizomes. Enticing foliage color in full sun is a welcome feature for gardeners who are willing to perform ongoing maintenance. Pruning to the ground every few years improves appearance. Clumps develop an arching profile and send up wheat-colored floral spikes in summer, reaching 3-4 ft. or taller depending on the frequency of supplemental irrigation. Wild rye grows in any soil except those constantly wet or dry and makes a suitable slope stabilizer if given adequate moisture. Give part shade inland; sun near the coast.

Melica imperfecta—coast melic grass. Dry, rocky hillsides and canyons in the Sierra foothills and coastal hills and mountains from San Francisco to Mexico are native homes of this tough grass. It lies dormant in summer until late-season rains begin. In gardens, it remains evergreen, upright, and fountain-like with monthly waterings but dries in summer-fall when not irrigated and can be cut nearly to the ground; regrowth begins with winter rains. Moist meadow conditions and part shade suit it very well despite a natural affinity for summer drought. Flower stalks laden with creamy white bracts over dark seeds rise a few inches to more than a foot above 1-2 ft. tall, 1 ft. wide, grassy tufts. Self-sowing is common but not difficult to manage.

Muhlenbergia rigens—deer grass. A dramatic, architectural presence seems to contradict the common name of this species—deer are not attracted at all. Easily grown in nearly any soil in full sun or part shade, its main preference is sunshine since it falters in heavy shade. Winter rains provide adequate moisture, but summer irrigation keeps foliage bright green. Long, thin blades arch gracefully and fountain-like in a broad mound 3 ft. high and 4 ft. wide. In summer, tawny flower stalks, radiating outward, carry very thin flower heads 3-4 ft. higher. Fast-growing, it can reach maturity from seedling stage in two seasons. Grassy mounds may be completely neglected for a couple of years without suffering; however, deer grass stays best looking when irrigated in the dry season, then cut down to 3 in. or lower every 1-3 years in winter before rapid regrowth in spring. In a natural environment, grasses can go years longer without pruning. Some gardeners groom occasionally by cutting out dead stalks and stems. A nearly identical, half-size, non-native version from Texas—pine muhly, M. dubia—may be more useful in small gardens.

Nasella pulchra—purple needle grass. Formerly classified in the Stipa genus, purple needle grass is the state grass of California, recognized for its once widespread presence before the onslaught of invasive exotic grasses spread by early Europeans and cattle grazing. Needle grass can be recognized from a distance by its masses of floral spikes that open with a purplish tint then display a silvery sheen. Floral spikes tower 2-3 ft. above shorter, leafy clumps 1-2 ft. wide. Heavy crops of individual seeds are produced. Each seed bears a bristle-like appendage, an awn, that reacts to atmospheric moisture by dropping and twisting enough to bury itself, a self-sowing technique that leads to germination and thicker colonies. (Awns are similar to “foxtails” that can pose a danger to pets.) This adaptable grass tolerates nearly any soil in full sun and sends roots 15-20 ft. down to access deep moisture. Clumps are long-lived, golden before lying dormant in summer when they can be cut back close to the ground. They green up again with winter rains.

Sisyrinchium bellum—blue-eyed grass. Not a true grass, but a member of the Iris family, blue-eyed grass is treated either as a grass or a small, flowering perennial at home in nearly any situation especially among rocks. It is found throughout California except in deserts and thrives in full sun or part shade. Summer dormancy with brown leaf blades is delayed in moist sites that also foster continuous re-seeding from copious seed production. In dry conditions, trim spent leaves to the ground; growth resumes with the onset of winter rains. Numerous named cultivars similar to the species offer a range of heights from only a few inches to nearly 2 ft. with similar width in tufts of fan-shaped foliage. Leaves have a bluish tint; flowers come in shades of purplish blue or white with bright yellow centers—”eyes”—and continue bloom for up to 6 months. Golden-eyed grass, Sisyrinchium californicum, is often taller, also fan-shaped, but with pale green leaves and yellow flower spikes. It grows best in wet, even poorly drained soils.

Sporobolus airoides—alkali sacaton, alkali dropseed. The common name of this warm-season bunchgrass indicates its adaptation to alkaline soils where it grows natively in the southern Central Valley and desert regions, mostly in sand or gravel with seasonal moisture. (“Sacaton” is Spanish for a type of grass.) It will grow, however, in nearly any but marshy soils, preferring some moisture rather than complete drought. Its 2-4 ft. height and width and deep roots can be used for erosion control, but showy, pinkish flower plumes also have an ornamental value in gardens. Airy flower heads may reach 5 ft. tall in summer, laden with seeds slow to self-sow. Grayish green mounds of somewhat coarse, narrow foliage turn yellow in autumn, then tan. Winter pruning close to the ground renews green growth with the start of the rainy season.

July 2022