The answer is "these are the hardy garden mums, but whether they come back next year is dependant on a number of things"
1. they need to be planted early in the fall - no later than Oct. 15th, and even then it depends on how soon freezing weather sets in. The plants need opportunity to root out into the surrounding earth & get established before it freezes solid.
2. they need to be planted somewhere where they will have good snow cover in the coldest part of winter to give them some insulation. In other words, on the lake bank where the snow is swept away, or on the south or west side of a building where the sun melts the snow in the daytime, but it freezes solid at night are not places to try and winter over a garden mum. The lack of snow and the thawing & freezing conditions in those settings will ruin chances of a garden mum surviving.
3. leave the dried stems of the plant intact. Don't trim them back until next spring when you see the new growth appearing. The tall stems will help catch leaves, and accumulate snow that will also help to insulate the plants roots from the cold Ontario winter.
Some growers will say there's no such thing as a "hardy" garden mum in our area, but with a bit of special care, you will probably be able to winter some over for next year.
For more information on growing garden mums, visit our website
http://www.huronridge.ca/growingtips_chrysanthemum.html
