Here is what I did.
Cut flower heads from stems and place on cookie sheet with parchment paper
Place flowers far enough away from one another so they dry evenly
Allow to dry for one to two weeks
Once dry mix with orris root or other fixative (patchouli, oak moss, or benzoin)
I used who but there is also powder or kernels. If you're using whole use one or two inch pieces depending on your batch. I made two small batches so I used half inch pieces for each batch. If using kernels you will want a teaspoon per ounce of potpourri.
Spritz potpourri with a mixture of 10 drops essential oil (I used lavender) and one ounce distilled water.
Be sure to get plenty on the orris root or fixative so it will hold the scent longer.
And voila! Find a pretty bowl and enjoy!