About half of the country moved into a slightly warmer zone in the Agriculture Department’s new “plant hardiness” map, an important guide for gardeners. Climate change may be a factor.
The maps are designed to tell you which plants will survive if you plant them. They’re widely used by landscape architects and the likes for that purpose.
Only which plants will survive the average lowest temperature. There are still years where the lowest low goes well below average and kills even some hardy native species, eg in Central Texas in Feb 2021 it hit 4° in zone 8b, which has an average lowest low of 20-25°. This map is a general guide and should not be relied upon alone by landscape architects. This USDA map doesn’t impart any information about average rainfall or humidity, average cloud cover, or average high temperature, elevation, soil type, and lots more…only the average lowest yearly low temperature
A lot of what you mentioned will have different effects on different plants, you would need a different map for each one. Lowest average temp seems to work well enough given it’s still widely used.
The maps are designed to tell you which plants will survive if you plant them. They’re widely used by landscape architects and the likes for that purpose.
Only which plants will survive the average lowest temperature. There are still years where the lowest low goes well below average and kills even some hardy native species, eg in Central Texas in Feb 2021 it hit 4° in zone 8b, which has an average lowest low of 20-25°. This map is a general guide and should not be relied upon alone by landscape architects. This USDA map doesn’t impart any information about average rainfall or humidity, average cloud cover, or average high temperature, elevation, soil type, and lots more…only the average lowest yearly low temperature
I agree that it’s not enough but it’s enough to rule out a lot of plants and narrow down choices.
I agree with that for sure, it’s a great starting place to judge what may work in your area
A lot of what you mentioned will have different effects on different plants, you would need a different map for each one. Lowest average temp seems to work well enough given it’s still widely used.