Judge Lisa Hart Cole cited the university's agreement to maintain the garden in perpetuity at the time it was donated in her Friday ruling, the Los Angeles Times reported.
The garden was donated to UCLA by Edward W. Carter, a retailing tycoon and former chairman of the UC Board of Regents, in 1964 on the condition that the university would take care of the garden in perpetuity.
UCLA said it would postpone the opening of any bids for the garden and an adjoining house and would consider its legal options. The opening of bids was scheduled for August.
"We're disappointed by the judge's ruling," said Kevin Reed, UCLA's vice chancellor for legal affairs. "This will be a setback with respect to the sale."
The university revealed plans to auction 2 acres of its property that contained a Georgian Colonial house and the garden. The university set the minimum bid prices at $9 million for the residence and $5.7 million for the garden.
In May, Carter's heirs filed suit seeking to stop the garden sale.