For many in northern Indiana, this has been a winter of discontent – filled with endless waiting until the snow melts, until temperatures creep above freezing for more than a few hours at a time.
For the region’s gardeners, add worrying to the waiting. They are worrying about what might have happened to their trees, shrubs and perennials as a result of the harsh weather – especially if those gardeners got a bit exuberant in their planting during the last couple of years.
In 2012, the U.S. Department of Agriculture reclassified much of the Fort Wayne area from growing Zone 5b to Zone 6a, basing the change on warmer minimum wintertime temperature averages between 1976 and 2005.
The change may have led some people to plant less-cold-tolerant species, believing they would survive. This winter, however, might lead to some rethinking.
Nick Greenawalt, meteorologist with the National Weather Service’s northern Indiana office in Syracuse, says both January and February of 2014 had lows at and below the low end of the old zone.
Fort Wayne, he says, had four days in January and February when the low temperature hit minus 15 degrees or below and 19 days when the low temperature was at or below zero. The lowest low was minus 16 degrees on Jan. 28 and Feb. 11.
Zone 6a is based on the coldest low temperatures averaging between minus 5 and minus 10 degrees; Zone 5b is based on those lows averaging between minus 10 and minus 15.
Our Purdue experts are telling us that it’s hard to tell how much damage may have occurred, says Dave Addison, educator for the Whitley County office of the Purdue Cooperative Extension in Columbia City. But he hopes for the best.
Most things should (survive). One nice thing about the snow is that it may have helped protect plants because it’s a constant 32 degrees and it’s a good insulator, he says. However, some may have gotten damaged. We’ll know more when it warms up eventually.
Deb Zunbrun, in sales with Arbor Farms Nursery in Fort Wayne and not a fan of the new zones, says plantings considered marginally hardy in the region are the ones most likely to see damage.
She includes among them crape myrtles, tulip trees, dogwoods, some types of magnolias and London planetrees, a European variety of sycamore touted for disease resistance.
But damage from low temperatures is only part of the picture this winter, she says.
Even things that are in the correct zones are getting damage, she says.
Evergreens in particular have been hit hard. Strong winds coupled with cold temperatures have led to browning or burning on branch tips, she says.
I’m seeing a lot of winter burn on arbor vitae, Zunbrun says, adding hemlocks, Norway spruce and white pines are other likely damage candidates.
She adds that branches on shrubs have gotten broken because of heavy snow loads – or snow falling off roofs onto foundation plantings. Also, she says, tree trunks and shrub branches have been nibbled by hungry rabbits and she expects homeowners will lose some perennials from an accumulation of ice-melting salt.
Arbor Farms still recommends only plants and trees hardy in Zone 5, Zunbrun says.
But Ed Farris says there’s been an up side to the weather. Farris is an educator for the Purdue Extension’s office in Huntington County.
The snow cover really helped the wheat crop by (providing) protection from bitter-cold temperatures, he says.
And, pest control experts are now speculating that populations of tree-damaging bag worms and emerald ash borers may drop because of the cold, he adds.
However, honeybees, already beset by disease, may have had a tough time surviving, Farris says, and not all plants are out of the woods.
Grape arbors, fruit and flowering trees might already have been suffering because of temperatures below minus 10, Farris says. Further damage might occur in upcoming weeks as plants come out of dormancy if a quick thaw is followed by temperatures below freezing, he adds. The best-case scenario is a long, slow thaw.
Indeed, Purdue experts are predicting a colder-than-normal March.
The snow and cold of winter usually continues into the first half of March. Based on the latest weather outlook, it could even persist late into the month, says Ken Scheeringa, associate state climatologist for the Indiana State Climate Office at Purdue.
He says forecasters expect a slightly drier start to the month, but are less sure about precipitation in the second half of the month.
Susan Littlefield, horticulture editor for the National Gardening Association in Williston, Vt., says Midwest gardeners need to be extra-patient this year. Some plants that appear dead or damaged might rebound with enough time.
She points out that zones are based on averages and trends, not an individual winter and survival can depend on soils and site selection as well as temperatures. But she also recommends erring on the side of caution if replacing plants.
When I think about planting long-term plants like trees and shrubs or a hedge, I tend to be real conservative and stick to the colder zone ratings. I don’t want to have a tree that grows for 10 years and then gets zapped in a cold winter, she says. Perennials and ornamental grasses are not as much of an investment, and you can be more experimental.
Here in Huntington, I haven’t heard of a lot of people changing what they’re planting because of (the new) zones, he says. I think a lot of people are skeptical and want to make sure they have success.