If you are thinking of turning your live Christmas tree into an outdoor tree after the holidays are over the ISU extension says it is possible. Patrick O’Malley, commercial horticulture field specialist with the ISU Extension says the key thing is to keep the tree inside as little as possible and he suggests a week or less. You should also put straw around the area where you are going to plant the tree to prevent the ground from freezing and also heavily mulch the area when you plant the tree. O’Malley says you shouldn’t try to plant a tree any bigger then five to six feet tall. He also says you should not plant a tree if it is below zero, as temperatures should be at least 30 degrees.