- Bay Area Garden Railway Society Internet Depot
Organization consisting of over 500 families who play with large scale trains in the garden.
- California Horticultural Society
Educational, nonprofit organization dedicated to bringing together gardeners and garden professionals to share experiences.
- Crow Canyon Gardens@ - San Ramon
- Marigold Farm
Offers links and information on local gardening sites, botanical gardens, and nurseries.
- Marin Rose Society
- Marin County
Guide to rose care, varieties, mail order sources, membership, and more.
- Master Gardeners of California@ - Santa Clara County
- Master Gardeners of Santa Clara County
- San Jose
University of California Cooperative Extension, with local programs, searchable tips organized by month, events, recommendations, and more.
- Milo Baker Chapter, California Native Plant Society
- Santa Rosa
Serving Sonoma County.
- Northern California Daffodil Society
Growing and enjoying daffodils.
- Redwood Empire Bonsai Society (REBS)
- Santa Rosa
Includes Bonsai demonstrations, hands-on experience, lectures, workshops, classes, slides, and sharing of members' plants.
- Robin Rosenberg's Garden Page
- Silicon Valley
With plan of the garden, information on different flowers, and photos of roses and flower arrangments.
- Ruth Bancroft Garden
- Walnut Creek
Xeriscaped garden of drought tolerant cacti and succulents including Agave, Aloe, Echeveria, Euphorbia, Haworthia, ice plant, and Yucca.
- San Francisco League of Urban Gardeners (SLUG)
- San Francisco
Responsible for developing community and greening 100 gardens all over the city, while promoting economic development and job training.
- Santa Clara County Rose Society
- Santa Clara County
With membership information, guide to good roses for the area, and more.