Since its introduction in 1978, Marlstone has been recognized as one of Sonoma County's premier Bordeaux-style wines. The Marlstone vineyard blocks occupy the center of the Clos du Bois Alexander Valley estate. The soil is a deep silty loam, which becomes increasingly mixed with clay as depth increases. Gravel underlays these soils at varying depths.
Water retention is such that the vineyard is usually dry-farmed each year.
Winter rains fill the soil profile and usually supply needed moisture for the entire season. The vineyards of Cabernet, Merlot, Cabernet Franc, Malbec and Petit Verdot were first planted in 1969. Over the ensuing years, the grapes were vinifed and evaluated. It quickly became evident that the vineyards produced exceptional fruit with great varietal nuance and character. Vineyard management has been specifically tailored over the years to enhance and maintain balanced growth and crop load in specific areas where soil depth or gravel areas vary.