I found this in Lois Hole's book: "Tender bulbs will not tolerate frost and overwinter only in cooler climates. In cooler climates, these bulbs must be dug up after light frosts have killed the foliage [...] Bulbs in this group include [...] gladious..."

If they are not hardy for this zone, the time to plant them is in the spring. although the cause of your bulbs not growing could be from something else, such as site drainage or bulb quality as you mentioned. I get some of my bulbs from the garden nurseries, some from big box stores, but I always look for the largest firmest bulbs without signs of rot.

I agree, probably something wasn't quite right with the bulbs themselves or possibly the soil. Glads should be planted as soon as the ground has warmed or they can be started inside with the bulbs sitting in a shallow tray of water and then transplanted after developing some nice roots and 6 to 8 inch tops. Glads are rather tough, they'll often overwinter in the open ground, I've had such occur many times here in zone 3 when a blanket of snow has arrived and maintained itself during the winter with little or no frost penetrating the ground.

Thanks guys for the feedback. I will definitely give it another try next year.

I put mine in the ground around the beginning of May - it took a long time for them to sprout but they are blooming now - it seems to me that it takes about 90 days before blooms show up so a good idea to soak and then plant.

Try http://www.peetersglads.com/ This Canadian company offers wonderful glads very healthy and an amazing variety to choose from, including some well priced collections. Your problem is definately with the bulbs themselves, I grow glads for cut flower sales and they are tough they can be prestarted in trays as twrosz suggested. Also, if you want to stagger the blossom time so not all bloom at once, plant every second one upside down.