The Major Problem with the USDA Zone Map

The Major Problem
 with the
 USDA Zone Map

The USDA Zone Map is undoubtedly a great tool
 to rate hardiness for landscaping plants. 
However this map is ONLY the AVERAGE
 coldest temperature, not the coldest temperature
 that is possible. In fact, with a very unstable
 climate (likely due to climate change) colder
 or warmer winters are far more likely. In fact
 there have been at least 2 winters in Indiana 
in the past 10 years alone that have seen temps 
colder than the zone I am in. I am in
 Indianapolis, IN. In the Winter of 2014 the temp
 dipped down to -15°F in Indianapolis, and
 -20°F to -25°F on the north side where I live. 
Indianapolis had a zone 5b winter in a zone 6a,
 I had a zone 4b/5a winter in a 5b/6a location. 
In 2019 I had a zone 5b winter and I am 
technically 6a bordering zone 5b. It is ALWAYS
 best to go with the colder side rather than
 warmer side due to this very reason.
 Indianapolis is technically zone 6a, in reality
 it is a solid zone 5. Southern Indiana is a solid
 zone 6 (which fits the current map). 
But Indianapolis area northward is a solid
 zone 5, Bloomington area south is a solid
 zone 6 (this fits the d 1990 map). The map
 really should be updated more than every 
20 years especially with a rapidly changing climate.
 Virtually the entire country moved up (warmer)
 a whole USDA Zone from 1990 to 2012 
(most recent). With my own experience
 the modern map is not correct in many 
locations. Indianapolis should have remained
 a zone 5 in the 2012 map. Only minor or
 perhaps no changes at all should have been
 made with the new map for Indiana. The climate
 is changing, but parts of the world are getting
 colder as the climate is disrupted from CO2 
emissions, as a result we have had colder winters
 than the map says we can have. I have had weather
 colder than the map says and reached the minimum 
temps at least 4 times in 10 years really says something to me. 

•

When landscaping please take this into consideration, 
and go a zone or at least a half a zone (5°F) colder. 
If you are a zone 6a, Do not use zone 6 and warmer 
plants unless it is protected and you or your customer are
 aware and are willing to take the risk.

•

Sum up: The 1990 map still is more realistic than the 2012
 (current) map which is too warm for lots or perhaps the whole country.

Bald Cypress vs Pond Cypress

*Quote is from Wikipedia

Bald Cypress vs Pond Cypress

Everyone has heard of the Bald Cypress, but few have heard of the Pond Cypress.
 The reason is because the two are recognized as the same species by most botanists.
 Pond Cypress is a wild variety of Bald Cypress.
 The bark of Pond Cypress has a darker more red tone than Bald Cypress,
 and the foliage is compacted into strings the point up.
 Pond Cypress is known for growing more upright than the Bald Cypress, but still has a 
spread with age. 
The both mature to a height of 75'-100' tall. 
The Bald Cypress has a width of 30' or so while the Pond Cypress has a width of 10'-15'.
The Bald Cypress extends up the Mississippi River up Southern tip of Indiana, whilst the
 Pond Cypress 
does not. 
The Pond Cypress grows up along the East Coast from Delaware down to South Florida
 in the Everglades
 over to Eastern Louisiana.
 The Bald Cypress grows in the same areas of the South and East Coast as Pond 
Cyprsss. 
The botanical name of Bald Cypress is Taxodium distichum. 
The Botanical name of Pond Cypress is distichum var. imbricatum. 
Ecologists however classify it as it's own species 
because it "Occurs mainly in still blackwater rivers, ponds and swamps without silt-rich
 flood deposits.
 It predominates in cypress dome habitats." 
Ecologists give the Pond Cypress this name: 'Taxodium ascendens' Whether they are
 the same species
 or not, 
they both began as the same species not long ago in the evolutionary timeline before 
splitting off. 
This is why they are so similar. While the Bald Cypress native habitat grows in those 
and more diverse
 environments than Pond Cyprsss.
 Even though both trees naturally grow mostly in swamps and wet areas they are 
surprisingly very
 drought tolerant.
 They are deciduous Conifers meaning they are not Evergreen as they drop their foliage
 in the Fall. 
The Pond Cypress is hardy in USDA Zones 5-11.
 The Bald Cypress is more cold hardy in zones 4-11.

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The first two pictures are mine, the others are from the Internet.

*Quote is from Wikipedia

Two Pictures of Pond Cypress landscaped in Carmel, IN (USDA Zone 5b)

 

Bald Cypress vs Pond Cypress

Pond Cypress Native Range

 

Bald Cypress Native Range