Certified GKH Gardening Expert
The recommended planting season for this plant, also known as Bishop's Weed, is spring or fall. If you get an early frost in your area, you may need to protect the new plants until they get established. If they survive your winter, they will definitely come back in the spring.
Here's an article for you: https://www.gardeningknowhow.com/ornamental/groundcover/snow-on-the-mountain/snow-on-the-mountain-plant.htm