The Finger Lakes area is New York's largest wine producing region. Over 100 wineries and vineyards are located around Seneca, Cayuga, Canandaigua, Keuka, Conesus, and Hemlock Lakes. Because of the lakes' great depth, they provide a lake effect to the lush vineyards that flank their shores. Retaining residual summer warmth in the winter, and winter's cold in the spring, the grapes are protected from disastrous spring frost during shoot growth, and early frost before the harvest. The main grape varieties grown are Chardonnay, Riesling, Gewürztraminer, Pinot noir, Cabernet Franc, Vidal blanc, Seyval blanc and many Vitis labrusca (American native) varieties or cultivars.