Q: I survived the polar vortex, but in the fall we planted a whole new landscape. We have new sod, perennials, shrubs, evergreens and two shade trees. It snowed a lot just before the real cold weather got here, and we didn't have any of the ice that some people got. Is there anything we can do to help the plants this spring or did the bitter cold harm them at all?

A: I assume the plants were appropriate for your region and not too exotic. In other words, were you trying some plants from farther south than your region that would be at risk from cold even in an average winter? Many gardeners want to grow plants that are pretty to them, but that are not suited for their landscape. It may be that they need more sun or more shade or that the soil in the garden is too wet or dry, but we often plant these plants anyway, hoping against hope that they will grow.

The same can be said about plants and cold weather, but we have a tool that we can look at to see if a plant is suited for our area. We have cold hardiness maps. The USDA updated their map in 2012. You will see cold hardiness zone maps printed in catalogs and garden books. Many plant labels will state the coldest zone the plant is hardy for.

Many gardeners misunderstand the map. It doesn't show the coldest temperature range that your location can get. It shows the average coldest temperature that was achieved during a few years. In the case of the newest USDA map, it shows the average coldest temperatures for the years 1976 to 2005.

Each zone on the map represents the average lowest temperature for an area, calculated using the lowest daily minimum temperature recorded for each of the years 1976 to 2005. The zones do not represent the coldest temperatures that occurred during those years or have ever been or ever will be in an area. For example, during this winter where we had very cold temperatures for a few days, if we also have a few days of warm temperatures for the lowest temperature, then the average for the year will not even notice the polar vortex.

The coldest temperatures for my area during the 2013 polar vortex were what the USDA Hardiness Zone Map showed as the average coldest temperatures for the years 1976 to 2005. Even though the media made a big deal about how the polar vortex was bringing record cold, it really only brought average low temperature cold to my landscape.

Since the hardiness maps only show the average cold and not the record cold, gardeners would be wise to choose plants that are capable of withstanding the cold of one or more zones farther north than what the map shows. This is more important on trees and large shrubs because they live so long. During their lifetime they will be exposed to record cold many times.

Small plants that are covered in snow, such as your sod and new perennials were sheltered from the record cold because of the snow cover. We don't call it a blanket of snow for nothing. Even the ice on the tree branches provides some protection from colder air.

My suspicion is that your landscape will come out in the spring just fine. The plants that may have the biggest problem are evergreens that did not have a very large root system and will have needles that turn brown as they dry out in the winter wind. If they green up this spring, they should be fine in other winters. The other potential problem area is where snow may blow off of lawns, exposing them to drying winds. Once they get a good root system they will be fine in the future.

Email questions to Jeff Rugg at info@greenerview.com. To find out more about Jeff Rugg and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.