i have 4 beautiful plumerias and i want to protect them from the jerusalem cold nights.previously i would just bring them into our house for the winter.since they have grown bigger and the house is the same size i thought of an idea.if i took them out of their plant pot (gently)and washed away the soil from their roots.and wrapped them up in old clothes.and lay them horizontally in a warm place in the house.is anything i said now harmfull? all i imagine that there is no activity in the plant in this cold weather.....that means that the plant does not know weather it is in a planter with soil or not.or does the horizontality change something in the plant that can cause some stress?.
I too store mine bare root over-Winter. Mine are placed in a plastic trash bags, with a lots of Perlite keeping the roots covered.. Just leave the bag open to the air & just place in a dark / cool closet. Horizontal or not.. doesn't matter.
David ! 
