Creeping Thyme between Paving Stones

Our church group has been restoring an old church and has placed flat stones in many areas for walking. We are interested in placing creeping thyme in-between the stones.
Could you please tell us if #P6463, creeping thyme, would be winter hardy in the Eastern Townships of Quebec, Canada and if plants in a plug tray can be put straight outside in early May? Also how far ahead would we have to order a tray?

Creeping thyme is hardy in zones 4 to 8. Eastern Quebec has zones 2 to 4 with zone 4 hugging the coast and then extending inland towards lake Ontario. If you are in this warmest area the plant will be winter hardy. If you do not shovel the snow on these paths and maybe add some straw to hold more snow, then the plants might even survive in zone 3.
Do not plant until the last frost date in your area. This probably is in late May. Shade the plants with newspapers, held down on the edges with stones, after planting to prevent sunburn.
Order plug trays at least twelve weeks ahead of the time they are needed. Not all varieties offered by Richters are in stock at all times; many are produced as they are ordered. To check what is available call Richters and ask to speak with the plug specialist.