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 First thing's first – winter hardiness. To some
extent, gardeners have been cheating Mother Nature annually for
years. We have this USDA hardiness zone map to use as a guide and
the information on the plant tag to tell us if the plant is going to
survive our winters. The hardiness zone map has been revised a
couple times now so you want to use the most current one as a
reference. The changes reflect long-term weather patterns over many
years. Visit the USDA site at
https://planthardiness. ars.usda.gov/ and zoom in on
Illinois or search by zip code. For example, St. Charles with a zip
code of 60174 registers as zone 5b with a temperature range of -15
to -10 degrees Fahrenheit for winter lows.
Where we get into trouble is purchasing a plant that is out of our
range. The kind of plant can make a difference too. Boxwoods are a
broadleaved evergreen, more susceptible to winter damage than a
deciduous shrub in the same zone. The same goes for rhododendrons
and versions of the broadleaved azalea.
This spring we are seeing winter damage on a variety of plants. Bud
and twig dieback is common for trees and shrubs, especially at the
tips where those buds were created late in the summer. Yellowing and
needle loss on yews and larger-needled evergreens can be seen. We
also may notice a loss of bloom show on forsythia, ornamental pears
and flowering dogwoods. In addition, if you have perennials that
typically overwinter with some above ground stems, they may be
killed down to the ground.
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In the home orchard, apples are the hardiest (flowering
crabapples are an apple so they are fine), and peaches are the most sensitive.
While there have been peaches survive this spring, there are many more that have
suffered severe damage to death. Other small fruits like brambles, strawberries,
and blueberries have suffered to varying degrees.
In the order of damage, sensitive plants will lose flower buds
first, then vegetative buds if the severe cold weather continues, then twigs and
branches. For plants that have a good reserve of nutrients, it can replace
vegetative buds, as long as there is no other damage. It will be late May into
June before we know for sure.
Dead wood will not come back, so pruning it out is appropriate. If you take the
wait-and-see perspective, get the replacements in as early as you can to allow
the new transplants as much time as possible to establish new roots in your
yard.
This damage is widespread throughout the region and there was not much that
could be done to prevent this kind of cold weather damage. For those gardeners
who did protect their sensitive plants from winter sun and wind, nothing could
be done to protect them from the very severe low temperatures. For those who
believe in alternative dimensions, you were not alone this winter.
[News Source: Richard Hentshel,
Horticulture Educator, University of Illinois Extension] |
