Question
I would like to dry my hydrangea blooms when should I pick the blooms and what is the process to preserve the colour ?

Answer
Good Morning!  You'll want to cut blooms when they've fully opened, but before they wilt at all.  Cut early in the morning and immediately submerge the cut stem into boiling water.  The hot water will force the air out of the stems.  You can either dry them upright in a vase and enjoy your hydrangea fresh and then again when they dry, or you may hang them upside down in a cool, dark and most importantly DRY place.  The color will always fade, but you can add a few drops of food coloring to the water (blue or red depending on the color of your blooms) to help intensify it and thus, have a deeper hue when they dry.