WHATS GROWING IN THE 21ST CENTURY GARDEN?
GLOBEL WARMING MEANS NEW VARIETIES & CHALLENGES
ANNA MAY KINNEY
No matter where you garden in North American, every gardener quickly learns that his area
is in a particular growing zone. The U.S and Canada are divided into ten zones, ranging
from the tip of Florida, #10 to the upper parts of Canada, #1. The higher the zone number,
the higher the lowest winter temperatures are in that zone.
For example; Floridas zone 10 has average winter lows between 30 and 40
degrees F., zone 3, the zone for the northern tip of New England and parts of Montana,
North Dakota, upper Michigan and the lower part of most Canadian Provinces, ranges from
30F to 40F. (This zone also includes mountain areas in Idaho, Utah, Colorado
as well as the Eastern Mountain ranges.)
When ordering seeds, live plants, roots or bulbs the consumer depends on this system to
decide which variety will make the winter in each area. Quickly you learn that if you live
in zone 3 you do not buy plants that are hardy in zone 4.
After decades of trial and error by scientist and researchers, who catalogued what grew in
each area, along with that of hundreds of volunteer gardeners throughout North America,
this valuable information was compiled into the zoning system we use today.
To complicate issues even further, within each zone there are micro- climates. My small
farm is a prime example of what happens if you live in a cold microclimate. While the
farms around me had low temperatures that related to zone 3 (even zone 4 in some low-lying
areas), my lows created zone 2 growing conditions. Making it impossible to winter over
even hardy perennials, like mums.
Between 1976 and 1984, there were weeks during January and February that the outside
temperature did not climb above 40 F. Then it slowly began to change. By the
1990s the change dramatically increased, the summer and winter lows became unusually
high, allowing specimens that would never grow here to strive.
1997 was my first year without at least one frost during June, July and August allowing
the annual vegetable and flower gardens to flourish without the hours of frost protection
I had grown accustomed to.
The greatest change has taken place with the roots, bulbs and perennials that winter over.
There are so many types that would never have made the earlier harsh winters, but were now
Having hardy bulbs survive a harsh winter is one thing, but Id never expect a tender
bulb (one that is dug up every fall and stored for the winter) to survive. In the fall of
1998, in my hurry to dig up, dry and store the tender bulbs for winter, a few were left
behind in the ground. Even with a sparse snow covering that winter, they were still alive
the following spring. A few annual flowers, were also alive, came back from their root
system and bloomed a second year.
Over the last five years, my micro-climate has gone from zone 2 conditions to zone 3,
showing signs it will not be long before it will be zone 4. (In fact with the mild lows of
this winter, we may well have made it to zone 4 already) Global warming appears to be in
only its beginning stages and if it continues like the experts say it will, what can
we northern gardeners expect?
First of all, there will need to be a major scientific effort put out to update all the
zone maps. Gardeners everywhere should record the changes in temperatures and growing
conditions in their areas and forward this information to some agency that can collect and
It will be become difficult for garden centers and other providers to know which plants to
recommend for which area, because people who live in zone three this year may find
themselves in zone 4 or 5 in a couple more year.
So what can a gardener do? I would suggest if you like a certain plant, but have been told
it will not grow in your area, and if your area is only one zone off on the zone map, buy
one small specimen of that plant and give it a try. If it makes it, then you can invest in
more plants of the same variety.
Along with the changing climate will be more variables, like less snow cover. In this
case, even plants hardy in your particular area may not survive the winter. What I have
done is to cover all my tender plants with lots of pine boughs. When it does snow, a few
shovel loads over any plant covered with boughs will increase the survival rate greatly.
When you look at your spring catalogs, remember this is the way it was for years, but
things are changing and you may want to experiment with plants hardy in the next zone.
Keep a record of your experiment and pass this information along to those who are in
position to inform authorities of the climate changes in your area.
In ten years, while we will not be able to go out our back doors and pluck an orange off
our own tree, there will be many species growing we never thought possible in our northern
climate. With the new plants we will also see an increasing amount of birds never seen in
this part of the world before. It will become even more important to grow a larger variety
of fruit bearing bushes.
My outlook for the gardeners of the 21st Century, is one of adventure, with new varieties
and challenges around every corner.