I am zone 7 in NC Piedmont near Charlotte. I do not dig my glads. I use pine straw mulch all year around. My glads have been planted 13 years and are still blooming. I do not have as many as 13 years ago (I have taken some out and some have rotted, they do not like wet feet) but what comes up blooms well with large flowers and good color. I will say that the glads down here do not do as well as they seemed to do up north.
Thanks for the post