Hydrangea Double Dutch Edam The Hydrangea Double Dutch Edam produces masses of beautiful pink double-flower heads, each densely packed out which makes them very eye-catching. Perfect for growing in patio pots and borders. Height: Up to 120cm (47?) when fully established Spread: Up to 120cm (47?). Caring for Hydrangeas Like all Hydrangeas the intensity of the colour is dependent on the soil pH. Hydrangeas like to be grown in rich moist soil and to give them the best start, stir in rotted manure or garden compost thoroughly. Alternatively, they can be planted up in containers in ericaceous compost.