To cultivate healthy hydrangeas in pots, it is essential to select a container that is 18 to 20 inches in both width and depth, and equipped with adequate drainage holes. This container should be filled with a high-quality, well-draining potting mix, rather than dense garden soil.

For optimal sunlight and placement, position the potted hydrangea in an area that receives morning sun and afternoon shade. 

Regarding watering, particularly during the warmer spring and summer months, daily soil moisture checks are imperative. Container plants typically dry out more rapidly than those situated in garden beds. Water the plant thoroughly until liquid drains from the bottom holes whenever the top inch of soil feels dry to the touch.