Carry a vase filled with water to the garden or the location where you will be cutting the hydrangea balls. Cut the hydrangea and immediately place in the vase.
Boil a pot of water. Cut the hydrangea stem to the desired length for arranging.
Place the hydrangea stem into the boiled water for approximately 30 seconds. This will eliminate the sticky, sap-like substance that forms on the cut stem, keeping the hydrangea from soaking up water.
Arrange the hydrangea as you desire in fresh water that is room temperature. The hydrangea leaf is also valued for its beautiful, lush foliage; consider using the leaves as part of your arrangement.