The name hydrangea comes from the Greek "hydor," meaning water, and "angos," meaning jar or vessel. This roughly translates to "water barrel," referring to the hydrangea's need for plenty of water. Because of this the hydrangea needs extra water to prevent wilting during transport and in the shop. A well suited pot size is very important to store enough water in the growing medium/soil. To give you an idea of how much water the hydrangea needs: it uses between 40 and 50 ml of water per day in standard conditions.