Yerba Santa: Just What the Doctor Ordered? (Hiking Edgewood)

Yerba Santa, the Holy Herb, is once more in bloom,

 at the Edgewood Preserve. 

On the last two docent hikes I led, a lot of folks have been asking my questions about how Yerba Santa was used historically. The following is extracted from a report that I wrote for a CA native plant class. 

Yerba Santa has long been used in traditional medicines by people in California. This information, however, is for interest only. I have no idea if any medical research supports using Yerba Santa in any of this ways, or if the plant is safe to chew, swallow, or apply to your skin.

What do you call it? Well for starters, It's a Hydropyllaceae, a.k.a. That's the Waterleaf family to those in the know.

The plant itself may be called... Eriodictyon californicum Yerba Santa, Mountain balm, Palo Santo, Holy Plant , or Holy Herb . “Yerba Santa” translates from Spanish into English as “Holy Herb’. 

Yerba Santa has been used locally as a medicine, both by pre-contact (native) peoples, and the Spaniards who came after 1769.

It’s scientific name Eriodic'tyon comes from the Greek erion, "wool," and diktuon, "net", because the undersides of some of the leaves have a fuzzy look. The species name simply means it’s found in California.

Physical Description
This plant is an evergreen shrub that grows to about waist height at Edgewood, though it can grow to be 3 meters tall. When Edgewood Yerba Santa begins blooming, preserve visitors on my docent walks take quite an interest in it. They ask me, "Why is it all black like that?". The black part they're asking about is leaves have a faint odor and  are typically infected with a black fungus, Heterosporium. The virus is not thought to hurt the plant, but it makes the leaves look ugly. 

Preferred Habitat
Yerba Santa is a typical chaparral plant. It grows profusely in this preserve on serpentine soil, in colonies that grow from shoots of shared underground roots.

Animal Uses including Human
Butterflies find the nectar of Yerba Santa very attractive.

“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. The plants can be harvested at any stage, but are best in the fall when the leaves are sticky and aromatic. 

The Kashaya Pomo recommend gathering the leaves just before the plant begins to produce flowers. The leaves, stems and flowers are used . 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. 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 and other aches and sores. 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 . 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. 

Other Uses
The Ohlone wove the leaves into skirts and aprons. I wonder if they included those pretty purple flowers into the designs :-)

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. Because of it's nature preserve status there are no longer livestock here, but the Spanish certainly grazed cattle in local meadows.

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