You can get Rhizomes from hopsdirect.com in the spring. Email them from their web page and they will put you on the mailing list. They are in Washington and that is where I will be buying mine from this spring.
Here is why you can't import them.
Hop Powdery Mildew (HPM)
HPM, a serious fungal disease of hops, was detected in late July [year] at several commercial hop yards in the northern Willamette Valley. This detection is the first confirmed report of HPM in a commercial hop yard in Oregon. This disease has the potential to be extremely damaging to hop yields and is a threat to commercial hop growers, hop enthusiasts and the brewing industry.
After the dramatic HPM outbreak in the Yakima Valley in 1997, Idaho and Oregon were the only two areas of commercial hop production that remained free of this aggressive pathogen. But now, with the detections of HPM near Puma and Bonner's Ferry, ID, and the detections in Marion County, Oregon, the pathogen has spread to all U. S. hop production regions.
Exclusion and Control
All three states with commercial hop production maintain quarantines prohibiting the importation of hop plants, rhizomes and cuttings. The USDA also maintains a Federal quarantine, which regulates the foreign importation of hop plants and rhizomes. Until very recently, control had been achieved by exclusion.
With the introduction of HPM into the Pacific Northwest, all hop growers, including non-commercial growers, will need to consider a number of changes in their cultural practices, including:
Removing all highly subsceptible varieties and replanting only resistant varieties
Roguing out all off-type or unidentified hops as their susceptibility is unknown.
Destroying all feral or or escaped hops in the production areas.
Plowing out aerial buds in the early spring to reduce overwintering inoculum.
Applying registered fungicides to all varieties per label directions (i.e. every 10-14 days, if HPM is observed in the growing area).
Composting or kiln-drying all hop leaf and vine material before returning it to the yard for plowing.
Removing or plowing all diseased material that remains in the yards after harvest.
Sorry that was so long but now you know.