The best place for your plants in zone 5 is in the ground where the roots can spread out and the plants have room to increase before winter. Lining out in pots is usually done in hot climates (zone 8-9) where the ground does not freeze or in a greenhouse.
The problem with trying to winter in pots in cold climates is that once the soil in the pot freezes, it can no longer drain. The top of the pot then acts as the edge of a swimming pool where during a winter rain or during a January snow melt, water puddles around the crowns. Once that water refreezes, ice shards will penetrate the crown creating an injury that may lead to rot. Some people get around this by putting pots in a protected spot like under the eaves of the house or on a porch, turning the pots on their side after the soil is frozen, or covering them....but again....the best place for survival is in the ground.
