Four principal areas of the southeast were chosen for trials gardens. None of the areas offered any additional protection from weather or pests and none offered any advanced irrigation systems. In essence the Eucalyptus trees were planted (throughout the growing season), watered in, and left alone.
A suburban home, 23 miles south of Atlanta in McDonough, GA (U.S.D.A Plant Hardiness zone 8A, average cold temp. 10 to 15 F). A total of 75 trees were planted. 2014’s coldest temp.: 6 degrees.
A 22 acre open field in Cumming, GA (U.S.D.A Plant Hardiness zone 7B, average cold temp. 5 to 10 F). A total of 75 trees were planted. 2014’s coldest temp.: 5 degrees.
A campground in Suches, GA (U.S.D.A Plant Hardiness zone 7A, average cold temp. 0 - 5 F). At 3,000’ elevation it is one of North Georgia’s highest elevation communities. A total of 125 trees were planted. 2014’s coldest temp.: 0 degrees.
What we learned form close to 400 individual plantings, with no additional care, soil amendments or fertilizers, minimal water, and little to no protection from the elements, is that some twenty Eucalyptus trees are cold hardy and thrive in much of the South (USDA Hardiness zones 6B and above).
Top performing cold hardy species for performance, growth rate, and physical attributes:
Eucalyptus nova - anglica
* Eucalyptus camphora
* Eucalyptus subcrenulata
* Completed three year trial
Poorest performing for (lack of) cold hardiness were: