I don't know the answer to your question, but I'm in SE Michigan and I've planted a few as late as early October and haven't lost them. Ideally though, I would be done planting by mid-September. If you already have the seed pods going, I'm sure you'll have them harvested in plenty of time to move your plants and plant new ones. I would not set any more pods on the plants you're planning to move at this point though.
