January General Chapter Meeting

January General Chapter Meeting
Monday, January 12, 2026 at 7:30 pm
Speaker: Roger Raiche, gardener, horticulturist, botanist, and conservationist

The Cedars - An Island on the Land

The Cedars of Sonoma County is one of California’s hotspots for ecological diversity. The geology of serpentine, an ultramafic rock, is characterized by high iron and magnesium content. It formed deep in the Earth’s mantle and surfaced through the subduction process. This “island” of mantle rock is embedded in Sonoma County within the Coast Ranges of Northern California. The Cedars is characterized by its dramatic topography, featuring deep canyons and rich, red-colored rock. Ultrabasic springs (pH > 11) create another layer of geology. These unique conditions have given rise to a rich ecology, including newly discovered microorganisms, insects, and seven endemic plant species.

Author and lecturer, Roger Raiche, is a founding partner of The Cedars Science Program and Planet Horticulture Landscape Design. Roger is renowned for his keen observational skills and encyclopedic knowledge of the California Flora. Roger discovered and published several new species, including three at The Cedars. Three other California plant species have been named in his honor. Roger has facilitated numerous scientific expeditions across a wide range of disciplines.

Roger’s observation skills have been complemented by his decades-long advocacy for the conservation of California native plant habitats. The creation of the BLM Area of Critical Environmental Concern ACEC at The Cedars and the permanent conservation of The Main Canyon at The Cedars were decades-long goals achieved. Roger is a California Native Plant Society Fellow. “Becoming a Fellow is the highest recognition CNPS awards its members. These members have accumulated extraordinary accomplishments towards the understanding, appreciation, and preservation of California native plants."

https://www.planethorticulture.com/the-cedars/
https://cnps.org/wp-content/uploads/2018/03/Fremontia_Vol37-No2.pdf