I have a question... And I ask with sincere curiosity... Can't you just apply for a permit to import plants and plant products from the APHIS? It does take some time to get granted a permit but once you do, it's good for many years.
I ask because I actually have a permit, I collect/grow/breed clivia, which usually required import of seeds/pollen/plants from South Africa, Australia, Japan, China and New Zealand. It's a pain to have to send the permit wait for them to receive it and then attach the permit for the return shipment, it takes some extra time but your product gets right through quarantine and customs with it.
If any members need to have their cuttings shipped to me and use my permit, I'd be happy to help and then send them to you lol.