I got away from using newspaper because I found that after 5 days there was more rot than if the plant is just sealed in a bag with nothing more than a spritz of water. I mean dip your fingers in the pond and then flick them in the bag, only that much water. They will survive 2 weeks in the mail, trust me, it happened and my plants were honestly no worse for the wear when they got to their destination.
I sent waterlilies wrapped in newspaper for years, they always suffered some mold or rot, my new method is also one used by my good friend Rich Sacher at American Aquatic Gardens. If you can guarantee 4 days or less, the newspaper is fine but if it will be longer than that by any chance, the plant in a sealed plastic bag with just the water from the pond allowed to drain off or a spritz from your fingers is ample.
Cheers,
Sean