I have a trumpet vine I planted this past spring when it was about 8" tall. It grew to be about 5' tall and climbs up a trellis part of a redwood bench seat with trellis back and sides/planter box on both ends that my husband build. The vine is in one of the end redwood planter boxes, which is about 18" square and deep with no bottom but goes directly into soil. We live in zone 5. What can I do to help it survive over the winter? I did not want to dig it up. Can I use bubble wrap around the base and mulch the top?