I have indicated my home’s location in Connecticut in Zone 6.  Ask your local nursery profession what zone you are in if you don’t know.  Note that the lower zone numbers indicate the minimum temperature each most plant can withstand.  The higher zone number gives you a range of average cold temperatures during winter in your area.  Last winter, the temperatures were plunged well below the -10 degrees for my area.   A harsh winter can be devastating.  When purchasing any plant, look for the appropriate zone for your area on the label.  If possible, it is always best to purchase plants that can survive in one zone colder than your zone.   This is often difficult to adhere to because we see a new plant, fall in love with it, and then we take the risk.  Open windy areas, raised beds and plants in winter resistant containers take a winter beating.  Through trial and error, you will notice winter kill occurring is specific parts of your yard.  Protect the base of these exposed plants with hay or extra mulch.   Many people burlap, but I never have and still my winter kill has been minimal.  Using evergreen anchors throughout will protect your perennials. Applying burlap is time consuming and back breaking work.  For more information about any special conditions that may exist in your area, consult with your local nursery professional.