I would contact the customs at the airport you are flying to in US and ask how to go about it and what to consider.
I just flew to Finland with 10 of my orchids and it was no problem cause I had contacted the customs and talked to them before hand. But of course this is in the EU and it is probably different in your case..
I think you could also try mailing it to yourself?
You could mail it to yourself if you had an export permit, import permit and CITES and phytosanitary certificates. The easiest way is probably to bring them in your carry-on luggage, and declare them at customs (you still need the CITES and phytosanitary certificates)