One of the newest agriculture interests in Georgia is the production of satsumas. Believe it or not, Thomas County had the most acreage under production until this year. Lowndes County will likely pass us in 2017.

These satsumas are between one and four years old and starting to produce fruit. The taste of the fruit on these young trees is not quite ready, however. Some will harvest trees for fruit, and some will use fruit for juice.

Producers will face challenges, such as disease, which is affecting many citrus orchards in Florida. However, the largest challenge for citrus growers is the cold. This is why Georgia is not a citrus state! The reason these satsuma trees are being planted is because of all citrus, satsumas have more cold tolerance than any citrus tree.

Many of you have some type of citrus tree in the backyard. I love satsumas, and I love it when you all send me away with a few satsuma oranges to eat. They are so sweet. Because of the sweetness of the satsuma, one grower made the comment about having a way to reduce sweetness once juice is processed. I thought, are you kidding me? My tea is not sweet enough until I can stand a fork up in it.

The lemons, grapefruits and sweet oranges in your backyard could be damaged by upcoming cold weather. You may need to think about cold protection for trees under four years old. It also depends on where your trees grow. Many of us have tall trees throughout the yard. These trees hold in heat, and citrus trees in these environments will not incur as much cold damage. There are many factors to consider.

Cold hardiness, factors

Citrons, lemons and limes are most easily killed by freezing temperatures. Temperatures from the mid- to high-20s will damage these. Sweet oranges and grapefruit are somewhat more cold hardy and usually require temperatures in the low- to mid-20s before incurring major damage to large branches.

Tangerines and mandarins are quite cold hardy, usually withstanding temperatures in the low 20s before significant wood damage occurs. And guess what? The satsuma has the greatest degree of cold hardiness. Properly hardened bearing trees will withstand temperatures as low as 19 to 20 degrees F without appreciable wood damage. Gracious.

Citrus fruits, on the other hand, easily freeze at 26 to 28 degrees F, especially when these temperatures last for many hours. A longer duration of freezing temperatures is required to freeze grapefruit than sweet oranges, and tangerines and satsuma fruits are more easily frozen than either of the former.

Another factor is cold acclimations. When we say “properly hardened trees,” we mean trees that have experienced some level of cold to help prepare it for low temperatures. Do you remember how warm it was last winter? We did not get freezing temperatures until January 2016. This is difficult for plants like citrus that need to enter the winter “slowly” so to speak. The shortening of daylight also tells plants it is time to prepare for winter.

Though we are warm, we have had some freezing or frost temperatures. Our cold acclimation has not been great, but it is better than last year.

Protecting trees

What do you do to protect the trees? Many of you hear about how irrigation is used for cold protection. This is true and one of the most common forms of cold protection. However, if you have one or two trees, it may be just as easy to wrap the tree with materials with good insulating properties such as fiberglass or foam rubber. Materials need to have contact with the soil. If you have lots of pine tree coverage, just one or two electric light bulbs under the tree will do the job.

If you want to use irrigation, start applying ¼-inch of water per hour when temperatures drop below freezing and continue until temperatures rise above 32 degrees F. If possible, support weak limbs to prevent breakage from ice. The ice should be clear and icicles should be present. If the ice is milky white, increase the volume of water being applied.

Remember, we are only protecting the trunks and lower limbs of young trees. Some of you have large grapefruit trees that you cannot reach over the top. We do not worry about these in the same way. As a matter of fact, ice from irrigation will likely cause large limbs on these trees to break. So, it is unnecessary.

Information from this article was taken from the UGA Publication “Citrus Fruit for Southern and Coastal Georgia.” For more information, contact the Thomas County Extension office at 225-4130.

Andrew Sawyer is an agriculture and natural resources agent with the UGA Cooperative Extension – Thomas County, 227 W. Jefferson St. For information call (229) 225-4130 or email at agsawyer@uga.edu