The Devon Valley microclimate is key to the quality of grapes grown on Clos Malverne. Although the valley is shallow it acts as a natural receptacle for the morning summer mists that linger around Stellenbosch. The valley is cooler than surrounding areas, significantly lengthening the ripening season, resulting in very ripe grapes. The vineyards are mostly planted on the gently sloping terrain of the valley. Seymour recently purchased two other farms very close to Clos Malverne. Dwars in die Weg has 11 hectares under vine (Cabernet Sauvignon, Merlot, Shiraz and Sauvignon Blanc). All vines are drip irrigated using water from the farm dam. Carlsrus has 4 hectares under vine (all Pinotage) using drip irrigation with water obtained from Teewaterskloof dam. Clos Malverne’s 10 hectares of vineyards (Pinotage, Merlot, Cabernet Sauvignon and Shiraz) also have drip irrigation using water from Teewaterskloof dam.