The majority of the gladiolus varieties are hardy zone 7, thus, you can leave your plant in the ground over winter. As for region that is colder than zone 7, plant your gladiolus in the spring period exactly after the date of your last frost.
Try to store the gladiolus corms in plastic mesh bags in a space with good air circulation. Also, store them where the temperature is about 35 to 50 degrees Fahrenheit. This will help keep the gladiolus corms steady for another beautiful bloom season.