Marin County has a diverse mosaic of plant communities, including:
- Forested Mt. Tamalpais
- Grassy slopes
- Ocean and bay marshes
Marin once supported native grasslands of perennial bunchgrasses and annual wildflowers. Today, these areas are now dominated by Mediterranean annual grass species or are used for residential and commercial development. Nonetheless, native wildflowers such as wild hyacinth, iris, owl's clover, and goldfields bloom in Spring.
California’s state grass, purple needlegrass, is a native perennial bunchgrass. Its extensive root system can grow 20 feet deep, helping to prevent soil erosion. In the valleys, various shrubs and plants exist along creeks, including:
- Big- leaf maple
- Oregon ash
- California pipevine
Climate and habitat
Marin County's climate and topography determine what plants can grows here.
Ridgetops and upper slopes
- Mixed evergreen forests
- Riparian scrub/forest
Northern facing slopes take on a cooler climate, making it a habitable environment for:
- Douglas-fir tree
- Coast Redwood tree
Southern facing slopes tend to be drier, making it a habitable environment for:
- Live oaks and bays
Native shrubs include toyon (California holly), and ceanothus (California lilac).
Tidal marshes at the edge of San Francisco Bay have been reduced significantly by development. Some marshes still exist at Bothin Marsh, China Camp, and other areas along the bay.
Few plants have adapted to the harsh environment of tidally-influenced fluctuating water and salinity levels. These include:
Coastal beaches on the Pacific Ocean are one of the harshest growing environments for plants. Coastal beaches experience strong winds, salt spray, and thin soils. Common species of the coast include:
- Beach strawberry
- Sea pink flowers
- Yellow sand verbena
Marin County has some special endemic plants, meaning they only grow in Marin. There are two rare, endemic plants that grow in only a few locations within the County:
- Tiburon mariposa lily
- Mt. Tamalpais jewel flower
Marin County also has populations of nonnative invasive plant species, including:
- Perennial pepperweed
- Yellow star thistle
- Big leaf periwinkle
- Scotch and French brooms
These species can change the soil chemistry to prohibit native species from growing or grow so densely that natives are forced out.
The Marin Chapter of the California Native Plant Society has plant lists for many of the county’s popular trails.