Answer: Citrus trees are susceptible to severe frost damage if temps dip below 32 degrees F, so it depends on how cold temperatures are where your friend is. Also, the trees can typically withstand a few degrees colder than the ripening fruit can. Kumquats are hardiest at about 18-20 degrees; limes are the most cold sensitive, with damage at 30 degrees. Ripening navel oranges are damaged when temps dip below 27-28 for more than 3 hours. Of course, soil and drainage is another consideration. I recommend your friend contact their local County Cooperative Extension office. They will have specifics on what plants will thrive in their locale. Look under the County name, or Clemson University Cooperative Extension in the phone book.
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