California Sagebrush

California sagebrush, or coastal sagebrush (Artemisia californica), like many plants in the coastal sage scrub, has adapted to our summer drought by having two growth forms. In the winter and spring, when seasonal water is available, the gray-green leaves are long, tender and feathery. Plants are lush, and grow rapidly. During the hot dry summer months, spring leaves wilt and are replaced by small, tough leaves, Growth slows or stops, transpiration is reduced and the plant may look dead or dying. Under prolonged drought, leaves may be shed entirely.

The pungent aroma of sage brush contributes to the characteristic fragrance of coastal scrub sage. When hunting, Kumeyaay would rub themselves with sagebrush to disguise their human odor.

Description ^{2,4,5,25,26,59}

California sagebrush is a much-branched, drought-deciduous shrub, 2-5 feet (0.5-1.5 m) tall.

The gray-green leaves are pinnately divided into 2-4 narrow segments with margins rolled under. There are two types of leaves: winter-spring leaves are 1½-2½ inches (3.5-6.5 cm) long, summer leaves are thicker and shorter.⁶ All leaves are strongly aromatic.

Inconspicuous flower heads are greenish or whitish, sometimes tinged with red-purple; 15-30 small flower heads hang along the terminal portion of the stems.  A flower head is composed of tubular, funnel-shaped or somewhat bilateral disk florets. There is no pappus. The tiny corolla is four- or five- lobed. Five stamens are united into a column around the style; stamens are only slightly exserted beyond the corolla. The ovary is inferior, inversely conical and translucent to white. The single style has two branches that arch or spiral from the corolla. There are up to 10 female disk florets around the edge and about 35 bisexual florets in the center. Flowers are wind pollinated and occur primarily during August-December.¹

The dried flower parts persist on the developing seed heads; fruiting heads resemble dried flower heads. fruits are numerous and small, 1/32-2/32 inches (0.8-1.5 mm) long, pale and conical with longitudinal ribs. There is one seed per fruit. They are primarily wind-dispersed⁵ even though the pappus is lacking.

Classification

California sagebrush is a dicot angiosperm in the sunflower family, the Asteraceae.^2,11 This is the largest family of vascular plants in the Northern Hemisphere.¹⁴³ “Flowers” of Asteraceae are made up of one or both of two types of flowers (florets): symmetrical disk florets and strapped-shaped ray florets. These are crowded onto a common base (receptacle), and together are often assumed to be a single flower, which we call a flower head ^11,44,49

Many other members of the Asteraceae occur in the Reserve. These include include bush sunflower (Encelia californica), goldenbush (Isocoma menziesii), and coyote brush (Baccharis pilularis).

The genus Artemisia species have inconspicuous flower heads that lack ray florets.² Other Artemisia species in the Reserve include wild tarragon (A. dracunculus),  California mugwort (A. douglasiana), and Palmer’s sagewort (A. palmeri).⁴⁸

Ecology

Like many species of the coastal sage scrub, California sagebrush has adapted to summer drought by becoming dormant or semi-dormant during dry months. Winter-spring leaves are feathery and thin and support high rates of photosynthesis; consequently they also have high rates of water loss. As summer drought sets in, spring leaves wither and a second set of smaller, thicker leaves is produced, resulting in reduced water loss, but much slower growth. ^5,6,34 Leaves may also have the ability to wilt in the absence of water and to recover quickly with rain.¹³ Roots are fibrous and shallow, able to quickly and efficiently absorb moisture, facilitating rapid rehydration and growth as winter rains resume.^5,6,13

The function of aromatic compounds (terpines) in the leaves is uncertain, but there are several theories: terpines released from leaves may inhibit germination of seeds below the plant, reducing competition (allelopathy);^5,14 they are unpalatable and may reduce grazing;^5,14 they are highly flammable and may help a fire to move quickly without damaging the root stock.¹³

Human Uses

In coastal Southern California, Native Americans used California sagebrush as a soothing medicine for poison oak,¹⁵ ant bites and measles,¹⁶ and as a tea for general illness.¹⁶ Wood was used for tools and construction.^15,17 The leaves were dried and smoked as tobacco,¹⁶ and the plant was used in a variety of ceremonies.^15,17 Kumeyaay Indians rubbed themselves with sagebrush to disguise their odor when hunting.¹⁰⁰

Although seeds were occasionally used for flour,^18,34 food did not appear to be a major use.

Early miners are said to have used sagebrush to repel fleas,³⁴ and others have used sagebrush twigs in sneakers to cure athlete’s foot.¹⁰⁰

Interesting Facts

California sagebrush is not a true sage; true sages are in the genus Salvia.¹¹

The main vegetation type for California sagebrush, coastal sage scrub, is threatened by development. The U.S. Forest Service has estimated as little as 10% of the original coastal sage scrub vegetation still remains.^5,14 California sagebrush is one of the plants propagated in the Nature Collective nursery and used for revegetation projects in the Reserve.