I live in a condo and my balcony is located on the southwest corner of the building. I live in Toronto, Ontario, Canada and my building is about 1 km away from Lake Ontario. I have about 30 Emerald cedars that are 6 feet tall in planters that are 2 feet tall. This is the first winter for my cedars since I bought them in the spring. Do I have to use burlap to wrap the cedars in the winter?