Question
can they be left in the ground for the winter? and if not
can i store them in the refrigerator for the winter in a
plasic bag?

Answer
Gladiolus -- officially -- are hardy to around zone 8.  But there's that list of exceptions that allow many people in zone 7 or even 6 to keep them in the ground all winter and still have flowers every year, which makes them then perennial and not exactly the forum for annual plants.

But here we are, so we'll continue.

Planting them deep and locating them near heat-retaining rocks or foundations boosts your odds of deja vu for these popular summer blooms.  Southern locations help, too; Northern locations hurt.

You have not supplied your location.  If you want to give me your zipcode, I'll confirm your zone.

As for the plastic bag storage, absolutely positively do NOT put these in any plastic bags.  Tubers and bulbs need air.  Plastic bags are good at keeping air out (to retain freshness and moisture).  You'll doom them if you put them in plastic.

No refrigerator needed, either.  Just keep them cool, and dry, and dark.  Unlike dahlias, which need a modicum of moisture to keep from drying out, Gladiolus are able to seal in their own moisture and get through the dormant downtime by staying dry and dark.

Give me your zipcode and we'll pick up from there.

THE LONG ISLAND GARDENER