If you live around cities such as Juneau, Alaska; Toronto, Ontario; Halifax, Nova Scotia; Kamloops, British Columbia; Spokane, Washington; Kansas City, Missouri; Columbus, Ohio; Denver, Colorado; Boston, Massachusetts; Detroit, Michigan; Warsaw, Poland; or Lanzhou, China; your plant hardiness zone is 6.
This means your average minimum winter temperatures are between 0°F and -10°F (-23.3 to -17.8° C). Just remember, however, the wide differences in the heat zones within this area: Kansas City receives on average 61-90 days over 86°F (AHS zone 7) while Detroit checks in at 15-30 days on average (AHS zone 4).
According to PBS’s The Victory Garden, USDA plant hardiness zone 6 is ideally suited to plants of East Asian origin. The zone straddles the 38°N zone unless significantly impacted by water or elevation influences (e.g. Juneau, Alaska- 58° N).
There is a north-to-south belt of the zone 6 in the high Andes of western Argentina and southern Bolivia in the southern hemisphere. The zone, however, is primarily restricted to the northern hemisphere because of its association with very cold and stormy interior continental type climates. We don’t find continental climates in the Southern Hemisphere due to the absence of a land mass large enough and far enough away from the oceans and its currents to generate this effect.
What are Hardiness Zones?
We define hardiness zones as geographic regions, most commonly based on USDA criteria that support specific plants, flowers, and trees. They usually define a minimum range of temperature that a plant or tree can survive safely in that zone.
If possible, it is a good idea to consult other planting-related maps such as first and last frost dates, and heat zones.
Canada’s Zone 6 Regions
In Canada, USDA zone 6 dominates the Columbia River and Okanagan Valleys of the Cordilleran Plateau of British Columbia, and the Great Lakes Lowlands south of Kitchener.
In addition it spots the southern and Atlantic coastal areas of Nova Scotia including Cape Breton Island plus the northeast coast of Prince Edward Island.
Agriculture and Agri-Food Canada lists Japanese maple (Acer palmatum), slender deutzia (Deutzia gracilis) and showy forsythia (Forsythia x intermedia ‘Spectabilis’) as shrubs indicative of this zone.
Zone 6 Regions in the United States
USDA Plant Hardiness zone 6 takes a wide sweep from patches within the western intermontane plateaus of Washington State (e.g. Spokane); they also stretch down to the higher hinterlands of Salt Lake City, Utah.
It continues northeast across the continent in a thinner belt through Kansas City, and on to Boston, Massachusetts.
With the influence of water, a leg of the zone stretches north to the eastern Great Lakes of Erie and Ontario and an offshoot shows up along the panhandle of Alaska (e.g. Juneau).
Europe and Hardiness Zone 6
Zone 6 generally forms a north-south pattern with its center in Poland.
To the north it stretches along the Baltic Sea coast up to Estonia, then west to include Stockholm, Sweden, and Oslo, Norway.
From the center in Poland, the zone to the south stretches as a mass from eastern Germany and Switzerland down to Albania and western Bulgaria.
Significant Zone 6 Regions in East Asia
An area of zone 6 runs from north of Beijing in a south-western belt to north of Lhasa, plus a mass in western China on the border with Kazakhstan.
The zone also becomes more significant in Japan and Korea.
Plant Options for Gardeners
According to PBS’s The Victory Garden, the following plants grow well within hardiness zone 6:
- American holly (Ilex opaca)
- California privet (Ligustrum ovalifolium)
- Common boxwood (Buxus sempervirens)
- English ivy (Hedera helix)
- Japanese maple (Acer palmatum)
- Winter creeper (Euonymus follunei)
Asian Plants Thrive in Low Temperatures
The low temperatures experienced in zone 6 encourages gardeners to carefully consider what plants work best in their zone, while still allowing many Asian-origin plants and others to not only survive, but thrive.