I recently aquired in trade some chrysanthemums. They are not the kind you get in Home depot. They have different "types" of blooms? (The only way I can explain the difference is to say look at http://www.kingsmums.com )

Now my question, how low a temperature can they survive? Can I plant them in the ground and mulch them for winter? Or do I have to dig them up? If I don't want to dig them up, how much mulch would I have to put to keep them alive thru winter? Can I put a flat 1' by 1' rock tile that I have, on them right before winter?

Thank you so much!