Answer: Glads are not terribly hardy and do not need a winter cold treatment. In fact, they will die if you freeze them. To keep your glads, cut off the tops, allow the corms to dry for a few weeks, then when completely dry, store them in paper bags (not plastic) in a well ventilated cool dry area. A good temperature to aim for is about 40 or 45 degrees.
If you missed some of the large corms or little cormel babies, they may survive the winter or they may not. Those that survive will sprout next summer. An easy solution is to pull them up like any other weed. You may also find them as you plant your new plants early next spring. If you find a large blooming size corm and you would like to keep it, simply transplant it as you would any other plant.
Enjoy your glads!
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