Last year I bought 5 Canterbury Bells plants which were fairly well established and already flowering. I never got around to planting them in the ground so I tried to keep them well protected (from too much hot sun/wind) and watered. At the end of the season they went brown and completely died back. Currently all that is left is a dry twiggy outline of the plant.

I'm fairly new to this whole gardening thing - but I thought they were prerennial as in they come back each year? At least that is what it says on the label.

How will I know if they are completely dead or just dormant?
What do the seeds look like? There are all kinds of 'bits' on the surface of the soil under each plant - if some of these are seeds I would like to try and germinate them.