I think this is the one I bought this year, have it in a hanging pot. Found this on the internet:

Hardiness: USDA Zones 8 - 11. Purple heart can tolerate a touch of frost, but it appreciates a blanket on cold winter nights. It will usually come back from the roots after a moderate freeze.

Propagation: Like other Tradescantias, this species roots easily from cuttings if the stem nodes are firmly buried in sandy soil. It is very easy to transplant.

Doesn't say anything about seeding, so looks safe. I'm hoping mine will overwinter in my semi-heated basement.

The blooms on mine stay open in the afternoon, much later than my hardy tradescantia do.