Hi jas4141 ~ I have done 2 or 3 ways of rooting & potted them for a year or 2 as well.

I'd remove the plastic cover & replace w/ burlap wrap or mulch ~ leaves or woodchips ~ sinking in a hole, pot & all is great, easier to plant in permanent home by Spring! The important thing is have a friend or neighbor water a few times while you're gone, pending on how much rain or snow can provide.

Most Hs are root-hardy in our similar zone ~ blooming is another story. A broken Kyushu stem, as thick as my middle finger, I've rooted stayed in the pot for 2 seasons before sinking in the ground ~ grew in leaps & blossomed. Now I intend to relocate in Spring to a better site w/ more room to grow, the 7x7ft size she'll grow to be.

Good luck & have fun where you Winter!