Experts and BHG readers answer.
Ordinary Gladiola bulbs aren't winter hardy in your zone 6 garden, so you'll have to dig them up and store them in a cool, dry place during the winter. However, if your glads are the hardy 'Nanus' variety, they'll be fine in the ground. You can transplant 'Nanus' Gladiola in either spring or fall. An extremely well-drained or dry site will make them happiest.