As we progressively move into Spring, many of us who love gardening realize that we have experienced an atypical winter —one like we’ve not experienced in several years. Along with numerous episodes of freezing temperatures came the challenge of trying to protect our landscape’s tropical or subtropical plants. Now that it appears that the winter of 2014 is almost behind us, we are faced with the challenge of assessing freeze damage to many of our cold-tender plants. While there are numerous issues that determine the extent of damage, we know that duration, or length of time that cold-tender plants are exposed to freezing temperatures, factors into the outcome. At one point, I can recall a local meteorologist commented that the Acadiana area had experienced around 60 hours of freezing temperatures. Anytime cold-tender plants are exposed to many hours of freezing temperatures, especially with the temperature in Lafayette dropping to 19 degrees, damage can be expected. Now comes the question of how to deal with plants that were damaged. Based on the phone calls I received within last two weeks and visits with employees at several retail garden centers, there are many people who have questions about assessing damage and what to do.
While there are a host of plants in our landscapes that will need attention following damage due to freezing temperatures, two of the most popular are citrus trees and palms. Both of these plants are susceptible to being damaged or killed by the temperatures we experienced. One of the points I’m making with gardeners regarding citrus is that kumquats and satsuma’s are the most cold hardy. Following these, in order of hardiness, are sweet oranges, with grapefruits, lemons and limes being the least cold hardy. Personal observations indicate, to me, we will lose some of these — especially younger trees that were not in a protected areas. The extent of damage is determined by several factors in addition to length of freezing temperatures: location of the plant, age, maturity and overall health of the plants. According to LSU AgCenter recommendations, it is best to wait until Spring is in “full swing” before assessing the damage to citrus. By the time we get into mid-to-late April and May, plants should show signs of new growth. We will be able to assess the damage, begin pruning off dead or brown branches and pulling out or cutting down those plants that show no signs of life. Another recommendation is to scrape the bark of branches or trunk and look for green or brown beneath the bark. Green is usually an indication of life. YET, if you want to be absolutely sure, you can wait until mid-May or a little later. One of the realities is that in South Louisiana, the limiting factor for citrus production is freezing temperatures.
In recent years, we’ve seen palms planted more frequently. There are many gardeners who are beginning to question whether or not it is wise to plant palms in our area at all. Of all the palms planted here, the queen palm has proven to be very popular. Unfortunately, it is also the least cold hardy of the palms we plant.
While all the palms suffered some damage, the vulnerable queen palms likely sustained the most damage and we should expect that some were killed. Others were damaged too and as a result will not grow out uniformly, with some of the new growth being distorted. Some palms will not recover. Palms are classified as angiosperms in the subclass monocotyledons and are more like bamboo and grasses than like other familiar trees in our landscapes. Stems or trunks of palms tend to be cylindrical in shape and usually have no leaf bearing lateral branches. There is usually one main growing point on palms known as the terminal bud located at the very top of the crown; this is where all leaves and growth arises. Once the growing point is damaged or killed—a possibility outcome with this winter’s freezing temperatures —that palm usually will not recover. Once again once that growing point is killed, the palm cannot generate a new one. That is why a palm should never be cut back from the top to try and control its height because it will die.
There are people who talked about protecting their palms by wrapping the trunks with insulating material or small Christmas tree lights; but, if nothing was done to protect the terminal bud/growing point, wrapping the trunk did little good. Since most palms are grown from seed, usually when it reaches a salable size, the grower has so much invested in the palm that it is expensive to purchase. We usually buy the larger palms; however, the larger they are the more costly they will be. So the question becomes how will we know how much damage was done or if the palm survived. For the time being, one can remove the brown fronds, but since palms don’t really begin growing until the soil temperature warms up significantly, it is recommended that a true assessment should be put off until mid-to-late summer. By that time, mother nature will show us not only the extent of damage, but whether or not a particular palm survived. As in the case of citrus, those palms that did survive will go through a process of recovery, so that means giving those plant all of the care and maintenance require to assist its recovery. Make sure they’re well watered, fertilized, and kept relatively pest free. A true assessment will have to wait until June, July or even August. Sometimes freezes will kill all the fronds, but don’t immediately assume that the palm is dead. It is always possible that the terminal bud/growing point survived. So before making a decision to remove it, wait! Give it some time, and look for new growth to occur at the center of the crown. Be aware that there have been cases where palms will begin to show new growth, then die.
Finally, when making the decision as to whether or not to plant palms, always consider the fact the even though there may have been several years of mild winters, the fact remains that it’s not a matter of “if,” but “when!” Eventually, we will, again, have temperatures similar to the ones we experienced in the winter of 2014!!!!
The sago palm is a popular plant that suffered damage and may have been lost this winter. Belonging to a group of plants called cycads, these are tropical or subtropical species that resemble palms in appearance, but that is where the similarities end. Sago palms are more closely related to pine trees. They are gymnosperms, producing seed bearing cones. Care of Sago, however, is similar to palms. For Sago palms that suffered damage, remove the brown leaves, take care of it and see if it recovers.
Gerald P. Roberts