Berkeley - UC Berkeley Botanical Garden

200 Centennial Drive
Berkeley, California 94720
Alameda County
Website
Phone: 510-643-2755

It's almost like taking a plant tour around the world when you visit the University of California Botanical Garden.  The garden contains over 12,000 plants from around the world; arranged by region.  This 34-acre, family-friendly park is open five days a week (normally, call ahead) and welcomes you. 
How to get there:
There are a few ways to get there depending on your starting point.  Check out the map for your best route. 
More info:
Visit the Garden's Website for more information.
Other things to do in the area:
Up in Richmond, Wildcat Canyon Regional Park has a lot to offer.  If you're staying in Berkeley, visit Tilden Regional Park and Oakland has a nice Zoo, the Oakland Museum of California and the Chabot Space and Science Center.