Karen Cambre, Sharpe, Kenneth W.
What a weather event to kick off 2018! It was cold enough to form ice on ponds in south Louisiana.
It also reminds us that tropical plants are designed to live in tropical environments and although we usually are not that cold, this was colder than most tropical plants could sustain.
Citrus that I have seen so far seemed to have fared remarkably well. Satsumas that have been planted for 2 years or more seem to have very little damage. Those newly planted trees did not do as well and other forms of citrus that are newly planted usually do even worse.
If you sustained freeze damage on citrus, your best approach is to take a wait and see attitude. Pruning to remove freeze damage should not take place until June. If you prune now, before you get new growth, you will prune off too much good wood. Even after you get new foliage it can take all the way through May before you can tell the full extent of damage. Then prune about June 1st to remove the damage and any new wood generated after pruning will have time to harden off before next winter.
I have also had a number of inquiries about pruning citrus in general. Pruning is notneeded yearly, but there are times that you may need to remove growth. When you have to prune to reduce size or shape the tree, it should be accomplished in the dormant season of January and early February.
On young trees it may be necessary to establish scaffold branches and to prune up low hanging limbs. After trees get older and are in full production it may become necessary to thin trees out for ease of harvest and spraying.
The most frequent pruning question I get is about the long shoots that grow at twice or triple the rate of the rest of the tree. Removing these long shoots will help control the height of the tree and keep the fruit harvest at a reasonable height. Follow those long shoots back to where they connect to a larger branch and cut the long shoot off at the point of attachment. If you just cut the shoot off in the middle to blend into the shape of the tree, you will create a witches broom and next year you will have 4 or 5 long shoots instead of one.
You can also remove crossing branches that clog up the interior of the tree and reduce airflow. I would also remove branches that are touching the ground.
While you are evaluating your citrus trees check the underside of their leaves for scale. This is a particularly pesky insect that sucks the leaves for plant juices and reduces production. Scale appear as raised bumps on the leaves. Usually scales are 1/16 to 1/8 inch in diameter and white, gray or reddish orange in color. Use dormant oils in the winter to suffocate and kill scale. If you wait until the heat of the year, dormant oils will burn leaves. Also, note that oils can burn foliage if applied within 48 hours of a freeze so check the weather report before spraying.
Berry producing plants such as holly or pyracantha do not have to be pruned routinely, but occasionally we have to reduce their size. Wait until after you have finished enjoying the berries and then prune. I would not remove more than half of the previous year’s growth since it is the 2017 growth that will produce 2018 berries. If you prune all of last year’s growth, you will miss out on the berry production in the fall of 2018.
Peaches and plums that need to be pruned should be pruned in the winter also.