I think ya'll are missing an important tip here. If you want your EE's to overwinter out side and your soil doesn't freeze, they still need to be DRY. The soil they are in over winter should be fast draining. You don't want the soil to be damp or wet. That will let rot set in. If your soil temp gets down into the 30's and is damp or wet. that's doom for them all even if you in zone 7, the soil still should be well draining and not wet during the winter. Remember, mulch deep, remove in spring when warming starts. For us northerners, dig, put and put in a nice warm place. let the leaves do their thing, remove the dead ones, no feeding, water only when the soid is dry. Watch out for spider mites. The only EE I have lost so far is the C. antiquorum, which I will replace when I have the money to do so. I feel it this way, dig it up, and keep your fingers crossed.
