USDA Plant Hardiness Zone Map (flowers, growing, Canada, northern)

[west336]

Check the official updated USDA Plan Hardiness Zone Map, which shows what USDA zone plants can grow in. This map should reflect the latest climatological readings.

USDA Plant Hardiness Zone Map#

My hometown area of the Twin Cities, MN moved from a 4a to a 4b, and in Minneapolis proper, a 5a zone. This used to be a big issue with people who love gardens but couldn't grow much because of the severe cold winters. Global Warming/Climate Change at its best!

[wheaties]

Is there a new version of the North America map?

[west336]

Originally Posted by wheaties

Is there a new version of the North America map?

This is it....or do you mean including Canada?

[wheaties]

Originally Posted by west336

This is it....or do you mean including Canada?

http://www.accuracyproject.org/w-PlantZoneMap40729.jpg
Yes, like this one.

[J&Em]

Nitram already had posted this same information on the new map 5 days ago. New Plant Zone Hardiness map released.


The most recent update to the Canadian version (which is somewhat "interactive" ) can be seen here: https://glfc.cfsnet.nfis.org/mapserv...20Canada&NEK=e The USDA is technically for the USA, not the northern hemisphere, but I'm not sure why they didn't include Canada unless they didn't get cooperation for enough new and in depth places to cover in making the new zone designations.

[cittic10]

People often mistake the cold hardiness map for a some holy grail that will tell you where plants will grow.
Compounding the problem are mail order nurseries who, rather than tell you what specific site conditions a plant requires, just lists a zone number as if it were really that simple.

This map is just for cold hardiness. It doesn't tell you what plants will grow where. It just tells you whether you can expect a plant to survive the average low temps. I wish people would stop relying so heavily on it for plant selections.

[J&Em]

Originally Posted by cittic10

People often mistake the cold hardiness map for a some holy grail that will tell you where plants will grow.
Compounding the problem are mail order nurseries who, rather than tell you what specific site conditions a plant requires, just lists a zone number as if it were really that simple.

This map is just for cold hardiness. It doesn't tell you what plants will grow where. It just tells you whether you can expect a plant to survive the average low temps. I wish people would stop relying so heavily on it for plant selections.

You've hit on a sore point for me since many people look for the easy way instead of understanding growing conditions. Nurseries on the other hand cannot help the map ties since that is how growers and the industry make generalized labels for broad areas of the country.

The maps are a general indicator of success when it comes to overwintering most perennial plants. There is also a cut off point where conditions might not get cold enough for some plants to set flowers for example so both ends of the range give you information about a plant and ideal conditions for growing it. The range is a useful tool but not the only thing you should consider. Sometimes people don't realize that say a zone 6 in Alaska, for example, is not quite the same as a zone 6 in Virginia, as another example, and give tons of information based on the zone and their location, ending up giving stupid advice that works in VA for the AK garden where it doesn't. Nothing sets my teeth on edge faster than the off hand "Oh I am in zone 6 and that plant definitely works in zone 6" without knowing anything else about the garden in question. Depth of coldness is not the same as length of cold season, and both are not perfectly reflected in the zones which also rely on first and last average frost free dates.

Heat zones are a reverse of the cold zone map. Some plants are not very heat tolerant. The summer temperatures may be close but full sun in the mid south is far more intense than full sun in the midwest. Heat zones take that into account, somewhat. More plant stakes have the information these days but it seems most people don't seem to have a clue about them.

Sunset zones were an attempt to further account for a combination of conditions, especially in the west where the heat zones are not always helpful in understanding how plants will do. It covers the entire USA and takes into consideration factors like elevation. I don't see too many plant sold with this information but it is a useful number to know anyway!

[cittic10]

Originally Posted by J&Em

Heat zones take that into account, somewhat.

The heat zone map that I use is based solely on the number of days each year with temps above 86 degrees.

Therefore a zone 1 at the upper elevations in Georgia would be the same zone 1 as seattle. But the stuff that grows in seattle can't always be expected to grow in GA and vice versa.