Are my Canterury Bells (Campanula Medium) dead?

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.
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scafell

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wrote:

Canterbury Bells (Campanula medium) also known as the bell flower, is an annual or biennial.
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