The Russian River Rose Company is a fun place to visit in Sonoma to see beautiful flowers in bloom; they have lots of roses for sale in the nursery, beautiful rose and perennial display gardens, and lovely fields of Bulgarian perfume roses. You can take the official tour to see how they distill the roses, or you can go to one of their open house weekends in April or May to wander the property yourself. The Bulgarian rose fields are special perfumery roses that the owner has imported, and their scent is amazing if you time your visit for peak bloom.
You can buy rare varieties of roses from their nursery — I always come home with a new favorite. They grow over 600 rose varieties!