Bancroft Gardens have played an important role with the Rotary Club of Walnut Creek (RCWC) over the years.  Phil Bancroft Sr. and Phil Bancroft Jr. were both members of the club.  The family was longtime pear and walnut growers in the Ygnacio Valley area of the city. For many years, Ruth Bancroft, wife of Phil Jr., planted a cacti and succulent garden adjacent to their home.  Over the years, Ruth became a well-known expert in Northern California for these plants.  The Garden Conservancy, inc., a national organization encouraged Ruth to open her gardens to the public so information on this specialty could be shared.

In 1975, the Ruth Bancroft Gardens Inc., was incorporated using initial funding of $10,000 donated by the Rotary Club of Walnut Creek.  (The amount was raised at the 1997 Presidential Ball.  Lance Mendes was president.  Angela Lansbury attended the affair and it marked the opening of the Gardens to the public.)

The garden is now recognized worldwide drawing visitors from many different countries.  RCWC continues to support the Gardens with financial and labor support.