First let me say I am not familiar with growing this plant (now called Tradescantia) in your climate. Depending on how cold of a winter you have it is best enjoyed as an annual which means it will die off after a frost. However, plants love to prove us wrong and zonal denial means they may survive a mild winter if you use the mulch trick. Just cover the planting with two to three inches of wood chips or bark chips mulch once the cold weather returns and the vines start to fade. This mulch can protect the roots from damage. In the spring rake off the mulch and you can cut back any top growth that looks damaged from the winter. With luck the roots will have survived and can quickly sprout new top growth once the weather warms and there is no longer danger of frost. Keep growing, Marianne Binetti