Muhlenbergia rigens — Deer Grass

This native California ornamental grass is commonly called deer grass, but deer generally avoid it. Easily grown in nearly any soil conditions, its main preference is sunshine since it falters in shade. Winter rains are adequate to promote vigor with little or no irrigation required during the summer, but summer moisture keeps its bright green foliage vibrant.

Though Muhlenbergia rigens is not indigenous to Sonoma County, it does range from Shasta County south to the Mexican border, as well as into Texas, New Mexico, and Mexico. It is generally found below 7000 feet in valley grassland, chaparral, yellow pine forest, and wetland-riparian plant communities. Historically, its long flower stems have been used by many Native American tribes for coiled baskets. Seeds were ground and used with corn meal for bread or mush. 

Muhlenbergia rigens is considered a warm season bunch grass with long, thin blades that arch fountain-like from a broad mound reaching 3 ft. in height and 4 ft. in width. In summer, thin tawny flower stalks carry narrow flower heads another 3-4 ft. above the bright, sometimes silvery green foliage.

This is a fast-growing grass that can reach maturity from seedling stage in two seasons. One of its finest characteristics is that it does not reseed easily and become invasive like the even larger pampas grasses to which mature specimens are sometimes compared.

Deer grass is tidy and well-behaved and may be completely neglected for a couple of years without suffering. However, it stays best looking when irrigated in the dry season and then cut down to 3 in. or lower every year or two in winter. It re-grows rapidly in spring. In a more natural environment, it can go for years without being pruned. It can also be groomed occasionally by pulling out dead stalks and stems with a rake.

Because deer grass reaches considerable size, it’s most appropriate for gardens with ample space. In flower, its arching form creates a dramatic display as a single specimen or when massed in drifts. Single plants create admirable statements especially when set against large boulders or architecturally sculpted hardscape or surrounded by attractive mulch. Plants set too closely together lose the boldness of their individual character.

Deer grass can be started from seed in pots early in the year and planted out in fall to take advantage of winter rains in becoming established. After a few years, mature plants may be divided following pruning and transplanted elsewhere during winter months. A sharp spade is needed to cut through the dense clump and fibrous roots. Though deer do not usually forage on deer grass, rabbits and ground squirrels and voles are known to nibble on young plants or to burrow into mature tufts.   

October 2019