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Welcome
To
Hardiness
Zone 5
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The move may be temporary, and
may be subject to review, but there is little doubt
that much of Wyobraska now resides in USDA hardiness
zone 5. The USDA hardiness zones are based upon the
average coldest winter temperatures. USDA Hardiness
Zone 5 is that region of the country with average
coldest temperatures of -10 to -20 degrees
Fahrenheit. We moved to Zone 5 from Zone 4—the
region with average coldest winter temperatures of
-20 to -30 degrees. Can you remember when winter
temperatures used to get down to 30 degrees below
zero?
In looking back, the move
appears to have begun several years ago. For the
past five years, winter temperatures below zero have
been rare, and even last year’s “coldest winter in
recent years” turned out to be more like a Zone 6
winter than a Zone 4 winter with only one or two
nights falling below -10 degrees.
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Homeowners with peach trees and
later season apple trees are also noticing the
effect of the longer season. Homeowner orchard
peach crops in Wyobraska were unheard of 20 years
ago, but are now commonplace. And later ripening
apples are no longer freezing on the tree in a
mid-September hard freeze. It stands to reason
that the move to Zone 5 will also mean earlier ripe
tomatoes, better peppers, and just possibly enough
heat for okra—if you’re in to slimy vegetables.
In the landscape, look for a little more fall color
on trees and shrubs. There are a number of trees
and shrubs that have been hardy enough to grow in
Wyobraska landscapes, but which have not had a long
enough growing season for their leaves to
consistently develop their normal red, orange, or
yellow fall color. English oak, northern red oak,
and many of the viburnums fall into this category. |
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Previous Articles
It's
Finally Spring - March 13
Spring Garden Calendar-March 20
No
Garden Left Behind-March 27
Planting Trees for a Cooler Earth in a Warmer
WyoBraska-April 3
Viburnums - Shrubs for Wyobraska Springs-April 10
Want A Water Conserving Lawn? You might already have
one-
April 17
Creating Long
Term
Tree-lationships April 24
Bigger, Bolder, Brighter,
Better—and Back In The Landscape May 01 & 08
Hardy Shrub
Roses
May 15
Another Look
at Native Plants
May 22
No Child
Left Inside
May 29
June
is Tree Care Month June 05
Summer Blooming Shrubs
June 12
Roses Are
Red.....
June 19
The Plants They will be Talking About Next Year at
the Garden Walk
June 26
Busy Summertime Gardens
July 03
Cutting Your Lawn Down to Size
July 10
July 17
Insect Paranoia
If It Will Grow In Wyoming...
July 24
Rain Gardens
July31
WyoBraska Native Grass & Wildflower Lawn
August 7
A Real WyoBraska Peach?
(Fruit Trees) August 14
Fall is for Planting
August 21
A Recipe for Enjoying Autumn Landscapes August 28
Seeing Red in your Landscape
September 4
Four Questions to Ask A Plant
September 11
September Plants
September 18
Mulch, Nature's Winter Blanket
September 25
2007 Articles
2006 Articles |
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Unless you’re paying close
attention, the changes in our regional climate are
easy to miss. But the climate changes have already
produced significant changes in Wyobraska
landscapes, and you can expect those changes to
continue. The most noticeable change is the now
almost complete disappearance of birch trees from
landscapes around the region. Colorado spruce trees
now seem to be going the way of birch trees with
perhaps a third of all spruce already gone, and
another third appearing to be under serious stress.
It is probably understandable
that a move from one hardiness zone to another is
first defined by the move’s harmful impact on plants
that have long been growing in the region. But the
move to Zone 5 that is now beginning to show up in
the Wyobraska landscape is also beginning to show up
in another way that has some avid gardeners
excited—with the successful establishment in
Wyobraska landscapes of a number of plants that
heretofore were “not hardy enough” to be grown here.
A move from Zone 4 to Zone 5
brings a number of climate changes that affect
landscape plants. It is almost certainly the
warmer summertime temperatures that are driving
birch trees and Colorado Spruce from Wyobraska
landscapes, but it is likely that the
correspondingly warmer minimum winter temperatures
will significantly increase the variety of common
landscape plants that can be successfully grown in
Wyobraska. Evidence of this can already be seen
around the region.
There is another significant
change that the move to Zone 5 brings to Wyobraska,
and this year’s beautiful early autumn weather is an
excellent example of this change—namely a noticeable
change in the length of the frost free growing
season. This change stands to bring the benefit of
shortening our long “visual winter”—that part of the
year when deciduous trees have no leaves. In recent
years we’ve seen nearly an extra month of leaves at
one end of the growing season or the other. This
year, with no frost in sight on the first of
October, that extra month is taking place right
now.
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The list of potential new landscape plants that will
be worth trying in our new Zone 5 landscapes is
long—especially since it is customary for avid
gardeners to try plants that are rated even one Zone
higher. So if you have had your eye on a Zone 6
tree, shrub, or perennial, it may be time to give it
a try.
Remember, though, that most
plant catalogues only rate plants by their cold
hardiness, and not by their soil adaptability. The
list of trees and shrubs that are hardy in Zone 4
but which will not grow in our Wyobraska landscape
soils is long, and the same will be true of Zone 5
and Zone 6 landscape plants. My suggestion is to
try plants that are already growing successfully in
the western regions of Zones 5 and 6. These are
more likely to be adaptable to our Wyobraska
soils—as well as our new hardiness zone.
Welcome to Zone 5. |