Cut fresh hydrangeas flowers from the shrub when they are in full bloom and before they begin to wilt and fade. Cut the leaves from the stems and trim the stems so they are short enough to fit into your container.
Place a 1-inch layer of desiccant into the bottom of the container.
Set the hydrangea flowers on top of the desiccant in an upright position so that the flowers dry in a natural position and shape. Allow the bottom layer of desiccant to help hold the stems and flower clusters in place
Pour desiccant into the container slowly. Use a spoon to place desiccant around the flowers in the clusters until you cover the hydrangea. Take care not to bend or crush the flowers as you add the desiccant to the container.
Close the container and place it in a safe place where it can remain undisturbed for several weeks while the flowers dry.
Inspect the flowers after one week and every two to three days thereafter to determine if the cluster is dry. The areas near the stem will take the longest to dry. When dry, gently remove the hydrangeas from the desiccant and shake upside down to remove all of the crystals from the flowers.