@petruske
Usually a "flat Rate" box from the USPost office works best. I use mostly medium sized boxes and you can get a lot of rhizomes in one!
Dig up the rhizomes and separate. Wash off all of the dirt (you could start them in a bucket of water (10% bleach)). Don't leave them too long in the bucket. Set out to dry off as you want ZERO moisture on them when you box them up. I sprinkle some anti fungal power on them as well after they have dried sufficiently. The foliage can be cut down to 8 inches or so. Box the next day or two. I punch a few holes in the box to allow air to circulate.
