Orange tree with fruit
image by Jenn/Flickr.com
Even in the warmest regions of our country, freezes do occasionally occur and can be devastating to orange trees. Orange trees are cold-sensitive and will not tolerate having to withstand freezing temperature for long. The result is either a damaged tree that might take years to recover, or a tree that's been killed back to its rootstock. Once the latter happens, you might as well remove the tree from the landscape since the fruit will be bitter. You can take steps to help an injured tree recover from frost damage.
Pick any fruit from the tree right after the freeze has occurred and juice them. Right after a freeze, the fruit is still good to use. If you wait too long, the oranges will become pithy.
Allow the leaves to remain on the tree, as well as the rest of the tree that might be damaged. Don't trim the tree immediately after the frost has occurred or soon after. Allow the orange tree to remain just like it is until spring arrives. Otherwise, you might inadvertently trim off sections of the tree that are alive.
Prune out obvious deadwood sections of the tree the first time you deal with any frost damage. Leaves that are damaged-looking but still green can remain on the tree as they are still alive and functioning.
Cut off the dead sections of branches on the tree by making your cut in the green section of the branch, just below the damaged area of wood. If you are unsure whether a branch is truly dead, don't cut it off. It may sprout back out with new growth; if it doesn't, you can trim it off later if it's truly dead.
Paint the freshly cut limb with a white latex paint that is water-based to seal the wound on the tree. This will help prevent diseases and will also protect the area from getting sunburned. Repeat this step on every branch you cut.
Prune the tree approximately one month later, to free it from any further frost damage that may now be evident. Sometimes it might take months for a limb that looks dead to show life, or for it to completely die.