California Yerba Santa (Californicum)

The California Yerba Santa (Californicum) is generally described as a perennial shrub. This is native to the U.S. (United States) has its most active growth period in the spring and summer . The California Yerba Santa (Californicum) has dark green foliage and inconspicuous purple flowers, with a moderate amount of conspicuous brown fruits or seeds. The greatest bloom is usually observed in the spring, with fruit and seed production starting in the summer and continuing until fall. Leaves are retained year to year. The California Yerba Santa (Californicum) has a moderate life span relative to most other plant species and a moderate growth rate. At maturity, the typical California Yerba Santa (Californicum) will reach up to 8 feet high, with a maximum height at 20 years of 6 feet.

The California Yerba Santa (Californicum) is usually not commercially available except under contract. It can be propagated by bare root, container, cuttings, seed. It has a moderate ability to spread through seed production and the seedlings have medium vigor. Note that cold stratification is not required for seed germination and the plant cannot survive exposure to temperatures below -3°F. has high tolerance to drought and restricted water conditions.

Uses of : Landscaping, Medicinal, Culinary, etc.

Ethnobotanic: Yerba Santa was highly valued by many California tribes including the Salinan, Ohlone, Miwok, Pomo, and Yokuts who continue to use it for various medicinal purposes. The Spanish who came to early California were so impressed with the plant that they gave it the name Yerba Santa, meaning holy plant. Yerba Santa was introduced to the Spanish Padres at Mission San Antonio de Padua by the Salinan tribe and it became one of three major medicinal herbs used at the mission (Heinsen 1972).

The plants can be harvested at any stage, but are best in the fall when the leaves are sticky and aromatic (Hedges & Beresford 1986). The Kashaya Pomo recommend gathering the leaves just before the plant begins to produce flowers (Goodrich et al. 1980).

The leaves, stems and flowers are used (Heizer & Elsasser 1980). They are either eaten or made into a tea, decoction, or poultice. The flowers and the bitter, aromatic leaves may be used fresh or dried. The leaves and flowers were made into a “bitter or sweetish-soapy” tasting tea that was drunk to relieve headaches and other symptoms of tuberculosis. Infusions of Yerba santa leaves and flowers were used to treat fevers, coughs, colds, stomachaches asthma, rheumatism pleurisy, and to purify the blood. The Kawaiisu drank Yerba Santa tea instead of water for a month to treat gonorrhea (Zigmond 1981). The Salinan used an infusion of the leaves as a balm for the eyes. Later, those at the San Antonio mission made eye balm by placing the leaves in corked glass bottles and allowing them to sweat in the sun.

Leaves were smoked or chewed to relieve asthma, coughs, colds, headaches, and stomachaches. Heated leaves were placed on the forehead to relieve headaches (Bocek 1984) and other aches and sores (Barrett & Gifford 1933). The sticky leaves conveniently stay in place upon the skin. Mashed leaves were applied externally to sores, cuts, wounds, and aching muscles. Mashed leaves were also used to reduce the swelling and relieve pain caused by bone fractures (Barrett & Gifford 1933). Yerba Santa, used alone or combined with other herbs, was applied to infected sores on humans and animals. The branches and leaves were burned in steam baths to treat rheumatism. The Ohlone wove the leaves into skirts and aprons.

Wildlife: Bees visit the flowers of Yerba Santa, which make a deliciously spicy amber honey. Seedlings and young plants are relatively nutritious and palatable but the bitter compounds in mature Yerba Santa shrubs discourage most large herbivores. However it is an important forage crop for black-tailed deer in the winter when other food sources are unavailable. Birds and small mammals eat the seed capsules.

Livestock: Goats will sometimes eat the leaves and stems. Cattle will avoid Yerba Santa in favor of more palatable plants, which can be a problem in highly grazed areas where it can become the dominant plant (Howard 1992).

Other: Yerba Santa can be used for rehabilitating and stabilizing disturbed areas (Howard 1992). The seeds germinate readily in disturbed soils. The shallow, spreading root system can help to stabilize areas subject to erosion caused by runoff.

General Characteristics

General: Waterleaf family (Hydrophyllaceae). Yerba Santa is a perennial evergreen shrub (5 to 22 dm) native to California and Oregon. The stems are black with shredding outer bark. The lance shaped leaves (4 to 15cm long) are thick and leathery with a glutinous upper surface. The leaves are dark green above with lighter green beneath and can have either smooth or saw-toothed edges. Older leaves often turn black due to a condition called sooty fungus. The white to purple trumpet-shaped flowers (8 to 17mm) grow in branched panicles at the stem ends. The flowers bloom from May to June or July. The small capsulate fruits (2-3mm) ripen in September and contain from 2 to 20 small black seeds.

Required Growing Conditions

Yerba Santa occurs from the Coast Ranges in California from Monterey County to the Klamath range in Siskiyou County as well as in the Sierra Nevada Range from Kern County in California to the Oregon counties of Klamath and Jackson in the north (Howard 1992). For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site.

Habitat: Yerba Santa grows below 1600-m elevation on dry rocky hillsides and ridges. It can be found in patches on chaparral slopes, forests, canyons, and along riverbanks. It is abundant in some annual grasslands and oak woodlands. Yerba Santa is often found in disturbed areas and early to mid successional communities.

Adaptation Yerba Santa is adapted to the hot, dry summers and mild, wet winter’s characteristic of the Mediterranean climate of California. Yerba Santa is a “fire-following” species (Emery 1988). Seeds stored in the soil for decades germinate readily during the first spring after a fire (Howard 1992). Older plants can sprout from their underground stems, called rhizomes, following disturbances such as fire.

Cultivation and Care

Gather seeds in September and October as the fruit capsules ripen. Yerba Santa seeds can be planted in the fall or early spring. The seeds will store indefinitely if kept in a dry, cool location. Prior to sowing, mix the seeds with several parts of moist sand. This helps to ensure even distribution. Seeds can be sown directly into a prepared bed or into flats filled with a mixture of equal amounts of soil, sand, and leafmold. Heating the seeds in an oven for 5 minutes at 194 °F may increase germination rates (Emery 1988). Alternatively the seed coat can be scarified in order to allow moisture and air to enter (Mirov & Kraebel 1939). This may be accomplished by rubbing the seeds between two pieces of sandpaper. Adding charate (burned and ground plant stems) to the soil may also increase germination success. When the seedlings are large enough to handle they should be transplanted into larger pots. The plants can be placed into the ground the following spring.

The plants are sunloving and do not tolerate shade. Plants may be grown in any texture of soil but prefer it to be slightly acidic and moderately fertile. The shallow roots allow them to establish in thin as well as deep soils. The plants are tolerant of serpentine soils.

When selecting a site keep in mind that after two years Yerba Santa can reproduce vegetablely through rhizomes. These underground stems can spread as much as 2.5 m in one year under excellent conditions (Howard 1992) and may overrun other plants (Halse 1993). This vegetative spread results in cloned patches with plants spaced from 20 to 25cm apart.

General Upkeep and Control

The plants should only be pruned in the spring or early summer.

Plant Basics
Category
Growth Rate Moderate
General Type Shrub
Growth Period Spring, Summer
Growth Duration Perennial
Lifespan Moderate
Plant Nativity Native to U.S.
Commercial Availability Contracting Only
Physical Characteristics
Bloom Period Spring
Displays Fall Colors No
Shape/Growth Form Colonizing
Drought Tolerance High
Shade Tolerance Intolerant
Height When Mature 8
Vegetative Spread Moderate
Flower Color Purple
Flower Conspicuousness Yes
Fruit/Seed Abundance Medium
Fruit/Seed Seasonality Summer Fall
Seed Spread Rate Moderate
Gardening Characteristics
Propagations (Ways to Grow) Bare Root, Container, Cuttings, Seed
Moisture Requirements Low
Cold Stratification Required No
Minimum Temperature -3
Soil Depth for Roots 6
Toxic to Nearby Plants No
Toxic to Livestock No
After-Harvest Resprout Ability Yes
Responds to Coppicing Yes
Growth Requirements
pH Range 7–8 pH
Precipitation Range 9–9 inches/yr
Planting Density 10–1200 indiv./acre
Soil Textures Coarse, Fine, Medium
Soil Depth for Roots 6
Minimum Frost-Free Days 250 day(s)
Salinity Tolerance None
CaCO3 Tolerance Low
Sustainability & Use
Leaf Retention Yes
Palatability Low
Fire Resistant No
Causes Livestock Bloating None

Source: USDA, NRCS, PLANTS Database, plants.usda.gov.
National Plant Data Center, Baton Rouge, LA 70874-4490 USA