If your plants have gone dormant but are still alive, after encountering 18 F. degree temps, I am assuming that while you babied them in their pots, you also allowed them to harden off enough to survive below freezing winter temps.

There are many ways you can accomplish raising these plants. The following describes just one of those methods.

Start with mixing the equivalent of a 3 cubic foot bag of garden soil with the same amount of (not-hot) composted manure into a large wheel-barrow.

Next, whether or not the soil is frozen, insert a garden fork and loosen a circle of dirt about 10 inches away from and all the way around one of the plants. Next, insert the garden fork deeply and lift one side of the dirt ball and roots of the plant; while at the same time, you backfill beneath that raised root ball with the dirt mixture from your wheel-barrow. Continue this process, progessing all the way around the plant until the bed is at least 6 or more inches higher than the level you want it to be once the dirt settles. Water well during the back-filling to help begin that settling process. Then cover the resulting, raised bed with at least 4 inches of mulch for winter protection.

If more than half of your soil mixture was used in raising the first plant, then add enough more mixed garden soil and composted manure to equally repeat your first plant's process for raising the second viticella.

I wouldn't worry about raising the clems themselves - nothing wrong with a deep planting and in fact is recommended on hybrid forms. Just mulch with whatever you have at hand - leaves, straw, topsoil from elsewhere on the property - to bring the soil level even. They should be fine.

You'd be surprised at how resilient these vines are with regards to cold. I have many clems in containers and they have all endured temperatures in the low 20's (if not the teens) from time to time without problems.