 |
| 6a |
Fahrenheit: -10 to -5 F
St. Louis, Missouri; Lebanon,
Pennsylvania |
| 6b |
Fahrenheit: -5 to 0 F
McMinnville, Tennessee; Branson,
Missouri |
| 7a |
Fahrenheit: 0 to 5 F
Oklahoma City, Oklahoma; South
Boston, Virginia |
| 7b |
Fahrenheit: 5 to 10 F
Little Rock, Arkansas; Griffin,
Georgia |
| 8a |
Fahrenheit: 10 to 15 F
Tifton, Georgia; Dallas, Texas
|
| 8b |
Fahrenheit: 15 to 20 F
Austin, Texas; Gainesville, Florida
|
| 9a |
Fahrenheit: 20 to 25 F
Houston, Texas; St. Augustine,
Florida |
| 9b |
Fahrenheit: 25 to 3 0 F
Brownsville, Texas; Fort Pierce,
Florida |
|
Taken from the National
Arboretum, this map shows in detail the
lowest temperatures that can be expected
each year in the South-Midwestern United
States.
Gardeners should also
keep in mind:
- Stress Factors.
We became aware of additional
stresses to plants during the 1970's.
Acid rain, gaseous and particulate pollution,
security lighting, and toxic wastes, among
many other stress factors, have significantly
increased the potential for unsatisfactory
performance of landscape plants. We need
to document the tolerances of plants to
these factors.
- New Plant Management
Systems. New techniques of planting,
transplanting, watering, fertilizing,
and providing pest control measures have
done much to increase the vigor of landscape
plants. But used unwisely, these same
measures can reduce plant hardiness.
- Artificial
Environments. We have
pushed the use of plants into totally
artificial environments such as expressways,
malls, elevated decks, and buildings where
plant roots are totally removed from the
ground and its warming influence. The
assortment of plants that can adapt to
such environments is proving to be very
restricted. Hardiness ratings alone are
inadequate to guide landscapers in selecting
the most successful plants.
|
