Although Valerian has a very pretty and strong smelling flower, it is the root that is used. The best time for harvesting the root is when the plant is dormant either at the beginning of winter or just before the plant starts growing again in Spring. I spent the last week of August stinking out the house as I washed and dried my newly harvested valerian root. It is not a very enjoyable job as cleaning the roots is difficult, time consuming and very smelly. The roots clump under the main plant and look a little bit like spaghetti noodles when fresh. All of the dirt needs to be washed away from the roots which as the valerian has been growing in our clay soil is a long and tedious job.
Once the roots are clean, they are then placed into the dehydrator to dry. They are quite thin so relatively quick and painless to dry. All this hard work is worth it as valerian root is an amazing sedating herb for most people (if you can mask the smell and taste). The only ones in our house who like the smell are the cats who kept me company for most of the time I was cleaning the roots.
Valerian is a very effective calming herb for most people but for a few people it does have the opposite effect - which is very unfortunate if you are trying to get to sleep. I have found that for these people (and my son with ADHD is one of them), that skullcap is a much more effective calming herb.
Research has shown that valerian works really well when combined with hops and passionflower as I have done in my Bedtime tea.