I intend to plant all of my roses and other plants in a big pot and put the pot in the garage so that they are safe from direct contact with snow and also are exposed to little less cold. Is there any harm in doing that. Second thought is to cover them with slanting transparent plastic sheet so that it is not in direct contact with plants and is open on both ends. By this plants will get sunlight and fresh air but will not be exposed to direct contact with snow. Is there any harm doing anyone of above two things.

Second question is that if I put gardening soil in a pot, perhaps I will have to give it little less water but little more frequently or is there anything else to worry about. thanks