Sonoma differs from Napa in the diversity of plantings and growers. While Napa is made up of mostly large estates, Sonoma consists of many small growers, of whom many were descended from European immigrants  that started growing grapes there a long time ago. Italian familes like Sebastiani brought old-vine grapes like Zinfandel, Carignan, and Petite Syrah to Sonoma a long time ago. Russian immigrants also named the russian river valley. In the past a lot of those growers sold their grapes to winemakers in the Central Valley or to the Italian Swiss colony at Asti. More recently, large scale estates that bottle their own wine have become more common.