Roussanne is a relatively rare variety of grape grown originally in the Rhône River Valley in France, and used in some white wines there and in the Tuscany region of Italy. The grape is also planted in various wine-growing regions of the New World, such as California, Washington, and Australia. The berries are distinguished by their russet color when ripe — roux is French for the reddish brown color russet, and is probably the root for the variety's name.
In France, the grape is traditionally used in blends with another white wine grape, Marsanne. It is the only other white variety, besides Marsanne, allowed in France's northern Rhône appellations of Crozes-Hermitage AOC, Hermitage AOC and Saint-Joseph AOC, and in Châteauneuf-du-Pape AOC. The Châteauneuf-du-Pape appellation also allows it to be blended into red wines.
The aroma of Roussanne is often reminiscent of a flowery herbal tea. Unlike some better known white wine grapes, wines based on Roussanne can mature gracefully, holding up well a decade or more after bottling.
It is a difficult variety to grow, with vulnerability to mildew, poor resistance to drought and wind, late and/or uneven ripening, and irregular yields.