What does zone 5 mean in the garden

A climatic zone is a classification of geographical areas based on the average coldest annual temperature.
This international standard for assessing the winter hardiness of plants was published by the US Department of Agriculture - hence the name "USDA climatic zones".

Source: With the kind permission of Ulmer-Verlag.
HEINZE and SCHREIBER, communications from the German Dendrological Society 1984

Explanations for the climate zone map

A climate zone map was originally created for the USA.

HEINZE and SCHREIBER (1984) developed a corresponding map for Germany based on this model. Since then, this map has been the only recognized climate zone map for Germany.

The map for the USA distinguishes between 12 climate zones (1 to 12), with 1 as the coldest and 12 as the warmest zone, each divided into two sub-zones "a" and "b", with "a" being the colder and "b" represents the warmer sub-zone.

Zones 6 to 8 are relevant for Germany; 1 to 5 and 9 to 12 do not exist in Germany.

At first glance, the map may seem a bit confusing for beginners, but that clears up quickly: The climate zones are arranged from west to east in 8 - 7 - 6, each divided into b and a, i.e. 8b, 8a, 7b, 7a , 6b and 6a. 8, 7 and 6 are differentiated by color: 8 is dark yellow, 7 light yellow and 6 blue-green, b is hatched in each case.

The confusing arises from the fact that the climatic zones do not simply run parallel, but protrude into each other and that there are also climatic islands, both warmer zones in a cooler one - e.g. B. Koblenz, Mainz and Ludwigshafen as well as Meersburg on Lake Constance are 8a islands in 7b - as well as cooler zones in a warmer one - z. B. are beeches in the Odenwald and Dingelst├Ądt in Eichsfeld 6b in zone 7a.

As can be seen without further ado, the map is roughly laid out. For example, the Mainz area - probably the Rhine-Main area - is a total of Zone 8a, there is no further differentiation, although there are of course considerable differences between the inner city of Frankfurt, the open areas between the localities in the surrounding area or even the Taunus.

When reading the map, it is therefore very important to classify your own location correctly:

Inner-city locations are more on the upper limit, maybe even a zone cheaper. The same applies to south-facing locations, in particular south-facing slopes. On the other hand, locations on the outskirts, near fields or forest, as well as northern locations, especially northern slopes, are more on the lower limit, perhaps even a zone less favorable.

In addition, the microclimate plays a role, which can be even more favorable through hedges and dense planting, and even less favorable in an open location. This can even go so far that clear differences can be felt within a few meters within a garden, depending on the amount of sunlight and shade.

It is advisable to observe the temperature conditions in your own garden and compare it with the temperatures of the local weather report. You can quickly see whether you are at the lower or upper end of the specified range or even in a different climate zone.
Perhaps the map will help one or the other of you to add the missing information "climatic zone" in the profile stored here.

Best wishes
Tetje and Klaus