I've sent cuttings, potted and bareroot passies through the USPS priority with no problems. If they are bareroot or in soil but unpotted I wrap the rootball with moist paper and cover that with plastic. I roll the vine up (loosely) and wrap that in newspaper then wrap the whole thing in another layer of paper and secure it in a box. If it's in a pot I tape paper over the soil so it doesn't fall out of the pot, wrap the pot in a baggie and do the same thing with the vine as a bareroot plant. If there's a lot of vine sometimes I will put a wooden stake in the pot before I wrap it to keep it rigid.
Karyn

Big thing with shipping is keeping the root-ball intact. Bare root is tedious as it gets bashed around & can get wounded.. I always ship them in the pot (pots are cheap) packing newspaper in the top then taping it all down.. Then taping the pot into the box. Fill the rest around the vine with peanuts.. And any shipper will do.

I've found the 8" x 5" x 6" "flat rate box"es turned inside out (so it ships for less than the flat rate) work Awesome.

Then 'course don't ship when it's Arctic & you'll be fine. Might be a bit tedious for the receiver to un-do all that tape, but worth it for an intact plant.

I use a small pot with 2 chopstick and a luch bag over top .First I put 1 chopstick on each end then take some moist paper on top of dirt to keep it moist for travel then maskin tape to keep dirt in.Then I use a brown paper bag over chopsticks and pot the chopsticks keep it safe in box and keep it from movin in shipping.In cold place some people use the heat packs but they only stay hot for 9 hours.

Angie you can get up to 72 hour heat packs and they do remain warm. I get them from the Aquarium supply store near me. They use them when they are shipping live fish. You can also buy them online. They are only a couple dollars each and are probably cheaper in bulk but I use them so infrequently it's not worth buying a dozen or more.
Karyn