Plants for Clay Soil: Grasses

We’re on a quest for interesting ground cover ideas to replace our East Bay lawn, and today I am looking at grasses. It may sound counter intuitive to replace a lawn with grass, but hear me out. I'm not looking to swap out one kind of grass for another, rather looking for drought-tolerant, California native grasses, and a whole new approach. Envision some combination of bark mulch, stone or gravel paths, and low creeping plants, punctuated with swaying grasses that shimmer in the sunlight.

I'm using an online tool to help me search: http://www.waterwonk.us/ (free, with a log on account). My search criteria include North Central Coast, Grass, California Native, and Reduced Summer Water. The tool recommends plants using Bob Perry's Landscape Plants for California Gardens. Here are some of my favorite results for our East Bay landscape in the Oakland Hills.

• Aristida purpurea (Purple three-awn) – clumping perennial grass. Finely rolled foliage grows 18-24 high, purple flowers and seed inflorescence grows to 30 inches. Remains evergreen throughout the year in mild winter zones; otherwise foliage and flowers fade and decline in fall, turning deciduous and sparse. Does best in a sunny location with little supplemental irrigation from spring through fall. California native; low water use – can withstand low summer and fall water, and regrows with winter rains. Does well in containers, borders, and in mass plantings to provide color and texture. Poaceae family.
• Bouteloua curtipendula (Sideoats grama) – grows in clumps to three feet high, with pale green, upright foliage and purple tinged inflorescence. Commonly planted in repetitive rows for mass effect, along boarders for contrast, and is stunning when backlit by the sun. Used for habitat improvement, and low-water lawns. California native, found all over North and South America. Does well with low water. Cut back in the fall to renew. Poaceae family.
• Bouteloua gracilis, cvs. (blue grama, mosquito grass) – clumping perennial that grows to 2 feet high, and half as wide. Inflorescences are set at a 45 degree angle from thin stems throughout summer and fall. Used for habitat plantings, natural meadow, and low-water lawn in warm areas. Withstands some foot traffic when cut to 2-3 inches high. Also does well uncut, and mixed with perennials. California native, found all over North and South America. Requires low amounts of supplemental water. Poaceae family.
• Festuca californica, cvs. (California fescue) – clumping species with pale green to gray-green foliage that forms 1-2 feet mounds. Flower inflorescences grow to 3 feet high. Grows in dry climate areas within chaparral and pine forest plant communities. The best stands grow in partial shade with reduced heat and moisture stress. Offers ornamental and restoration value in gardens and landscape. Plant in large drifts, casual masses, among trees, on slopes for erosion control, and for habitat. It is a good understory plant to California oaks, with low summer water needs. Poaceae family.

California fescue – grows under oak trees
Photo posted by Daderot (Creative Commons)

• Leymus condensatus, a.k.a. Elymus condensatus, cvs. (Giant wild rye) – large, wild rye species with coarse medium green foliage, clumping habit, and flower spikes 6-8 feet high. Spreads by underground rhizomes. Valued for landscape restoration projects. California native. Cool season grasses that are adapted to heat. Low water use, but does better with some water. L. c. 'Canyon Prince' has blue green foliage that grows 4-5 feet tall. Poaceae family.
• Muhlenbergia rigens (Deer grass) – robust species with mounding habit to 2-3 feet high. Foliage is narrow pale green, with long arching flower panicles to 4-5 feet tall, cream color in spring, then fading to straw by the end of summer. Found in gravelly or sandy washes, but is very adaptable. Grows in coastal, inland, valley and desert regions. Tolerates heat, aridity, and low amounts of supplemental water. California native; low water use. Cut back in the fall to renew, and divide periodically in fall or winter. Plant in large masses, mixed among boulders, or in containers. Poaceae family.
• Nassella cernua, a.k.a., Stipa cernua (Nodding needle grass) – robust, clumping grass grows to 3 feet high. Open habit with large inflorescences that produce nodding action when mature. Leaves are sparse and fine in texture. California native commonly grows in scattered locations through the coastal sage, chaparral and foothill woodland plant communities. Very low water required. Used for grassland restoration projects, and as an accent plant. Poaceae family.
• Nassella lepida, a.k.a., Stipa lepida (Foothills needle grass) – clumping grass grows 12-24 inches high, and inflorescence that reaches 30 inches. Often used in mass plantings, and in restoration projects around oaks. California native that grows within the coastal sage, chaparral, and other foothill plant communities. Uses very low water. Poaceae family.
• Nassella pulchra, a.k.a., Stipa pulchra (Purple needle grass) – clumping grass grows to 18-24 inches, with fine textured foliage that grows to 3 feet. Awns have a purple hue in early spring, turning to a light wheat color. California native that once covered much of the California grasslands (the state grass of California). Used in restoration projects. Very low water required. Survives winter rain, but should not be watered during its dormancy in summer. Poaceae family.
• Sporobolus airoides (Alkalai sacaton) – robust, warm-season grass, with foliage mounding to 12 inches high and inflorescence to 3-4 feet high. Flower panicles are branched and produce a delicate, transparent look in mid-summer. Commonly found in alkaline soils in dry areas affected by seasonal flooding. This species can endure drought, and tolerate heat, sun, and aridity. With its deep roots, this grass is planted for soil stabilization, as well as its ornamental value. Plant among boulders with southwestern plants. California native; low water use. Poaceae family.

Good sources:

• Annie’s Annuals and Perennials: http://www.anniesannuals.com/
• Bay Natives: http://www.baynatives.com/
• Berkeley Horticultural Nursery: http://berkeleyhort.com/index.html
• California Flora Nursery (no mail order, but located 63 miles north of Oakland/Berkeley): http://www.calfloranursery.com/
• Desert Mountain Conservation & Development Council (no mail order, but pick up in designated location, and on designated date and time): http://desertmountainrcandd.org/
• Las Pilitas Nursery (Santa Margarita): http://www.laspilitas.com/
• The Watershed Nursery : http://www.watershednursery.com/