Ok I live in western kansas we get about 2 to 3 weeks of single didgit lows and teens for the highs. Do you think I will have winter kill on the roots if I just leave my planter above ground. Or should I bury it... I really don't want to dig a 16 foot long 3.2 food wide and foot deep hole haha here is what I have set up so far cascade cintennial Chinook wilmette