Black sage is native to the low to medium elevations of the coastal ranges of California and adjacent Baja California. The plant is a medium sized shrub that is three to six feet tall and three to five feet wide. The plant is drought deciduous. That means that it loses some leaves in response to summer drought. This is a characteristic of plants of the coastal sage scrub plant community. The foliage is fragrant and dark green. The stems carry whorls of small, light bluish flowers in late spring and early summer.
Black sage is recommended for Sunset zones 7-9, and 14-24 or USDA zones 8-10. Plants can be grown in full sun but are tolerant of some shade. The plant is drought tolerant but not recommended for the true desert, Sunset zones 10-13.
Without additional irrigation, the plant needs about 15 inches of rainfall. To keep the plants from losing many leaves in the summer, they can be watered sparingly, but this also tends to shorten their life. Otherwise, it is a long lived sage. Trimming should be done after flowering. This encourages new growth in the spring and keeps old growth from rotting out in wet winters. You may want to wait to trim until that plant has gone to seed, for quail and small birds like the seeds. The plant is not picky about soil and can grow in sand or clay.
Seeds need light in order to germinate. Germination of seeds buried in the soil is inhibited unless charred wood is present. Branches will root where they touch the ground.
At least four cultivars exist:
- ‘Green Carpet' is up to 2 feet tall and 2 feet wide;
- 'Repens' is up to 1-2 feet high and 4-6 feet wide;
- 'Shirley's Creeper'; and
- ‘Terra Seca' is reported to be extra tough and is up to 2 feet tall and more than 6 feet wide.
Hybrids with other Salvias also exist. These include:
- ‘Calamity Jane' is 4 feet tall and 4 feet wide;
- 'Dara's Choice' is 2-3 feet tall and 3-6 feet wide and sometimes subject to verticillium wilt; and
- 'Mrs. Beard' which is similar to ‘Dara's Choice' except that ‘Mrs. Beard' has grayer foliage and lower growth and is resistant to verticillium wilt.
The seeds were eaten and the leaves used as flavoring by Native Californians. Also, the leaves were used medicinally and studies have shown that the leaves contain a substance that has antimicrobial activity.
In the wild, populations of black sage are decreasing. This is because of increased frequency of fire and invasion from non-native plants like mustard and some grasses. Also the plants are sensitive to air pollution.
Black sage can be a useful member of the California native plant garden. It usually needs no supplemental water and under proper growing conditions can live for years. It provides a neutral green background for small shrubs, perennials, and annuals, or the lower cultivars can be used as groundcover. It provides food for birds, honeybees, and native bees and shelter for small animals.