Temperatures in December 2022 were very damaging to many citrus in North Florida. It is necessary to give plants plenty of time into spring and summer to see if they will regrow and where that growth will occur. Learn how to care for your citrus that is suffering from cold temperature damage with Beth Bolles, UF IFAS Extension Escambia County.
Several times each month I am diagnosing shrub and tree problems in Escambia County that are related to the same issue, improper planting. Symptoms of this problem can be slow growth, leaf browning, and dieback. Sometimes under stressful weather conditions like drought, plants completely die.
This is a difficult sight for homeowners who have invested time and money in a tree or shrub to enhance the landscape. In some cases, the planting issues can be fixed but there are other times when a new plant will need to be installed.
The good news for homeowners is that this is a completely preventable issue. The University of Florida has excellent publications with photos about installing and caring for trees and shrubs. My Panhandle colleagues and I have also shared numerous articles and videos on proper plant installation.
Care must be taken during installation to set your plant at the correct depth. Even if a landscaper or nursery is installing the plant for you, check their work. Make sure the rootball is cut or sliced, it is not set below grade, that any straps holding the rootball are cut after it is set, and proper backfilling occurs without soil over the top of the rootball.
You don’t want to find out later in the season or even year’s later that your plant declined just because of planting problems.
Tropical milkweed, Asclepias curassavica, has become a commonly grown monarch host plant in many gardens. It grows very well in our climate and survives into Fall and Winter during many years. This long life of Tropical milkweed is not necessarily a good trait for the monarch butterfly. In the Fall, monarchs are in migration mode and need to move out of our area to overwinter in warmer climates. Live host plants that are found during migration may interrupt the process. An additional problem is that Tropical milkweed may be host to a disease caused by a parasite that can impact the health of Monarch butterflies. The best tip to help our migrating Monarch butterflies, is to cut back your Tropical milkweed to the ground each Fall or better yet, grow native milkweeds that usually die back on their own.
We grow many types of hydrangeas in North Florida. In order to prune your hydrangeas at the correct time of year, you need to identify which types you have in your garden.
Bigleaf hydrangea (Hydrangea macrophylla)
Bigleaf hydrangea (Hydrangea macrophylla) comes in mophead and lacecap flower forms. They bloom on old wood, so prune in summer after blooming is finished. Repeat bloomers, such as ‘Endless Summer’ bloom on both old wood from the previous year and on the current season’s wood. You can prune after the first bloom and still get a bloom later in the season.
Oakleaf hydrangea (Hydrangea quercifolia)
A native hydrangea that blooms on old wood, so prune after flowering. This type requires little pruning, only
to maintain size and shape.
Panicle hydrangea (Hydrangea paniculata)
These shrubs bloom on new wood, so prune in winter or early spring before new growth emerges. ‘Limelight’ and ‘Pee Gee’, are examples of this type. Plants only require pruning to shape or thin out the shrub.
Here are some additional pruning tips for your hydrangeas.
For all types, check for winter-damaged wood in early spring. Remove all dead branches before buds start to open.
Some plants need rejuvenation pruning. Old wood may die back or be less productive, so in early spring remove very old stems at the base. This stimulates new growth.
Deadheading flowers (cutting off spent blooms at a set of leaves) can happen as needed.
Citrus canker has made its way to Escambia County and may be more widespread that we realize. This bacterial disease was first seen in Northwest Florida almost 10 years ago in Gulf Breeze. Given time and the ease of transmission of this disease, we are now seeing affected citrus trees in both the east and west portions of Escambia County.
This disease is specific to citrus with grapefruit, lemon, and lime being the most susceptible to infection. The disease can infect all above ground tissues and often enters through natural openings and wounds of leaves, stems, and fruit. If you find an infection early in an isolated area of the tree, you can prune out and double bag the affected tissue for disposal. Often times, the disease is noticed only after a considerable amount of tissue and fruit are affected making it difficult to keep the disease in check.
Since the bacteria is so easily transmitted through rain and wind, it is difficult to prevent movement during our frequent storm events. People can also spread the disease by movement of unregulated citrus trees, on equipment, and even on clothing.
Citrus canker lesions appear on both the upper and lower surfaces of the leaves. Photo by Beth Bolles, UF IFAS Extension Escambia County
Lower surface with citrus canker. Photo by Beth Bolles, UF IFAS Extension Escambia County
If you suspect a citrus in your landscape has canker, do not bring a sample to your Extension office for identification. Take a photo of plant symptoms of upper and lower leaves, fruits, and stems so that your local Extension educators can assist with identification. The University of Florida publication https://edis.ifas.ufl.edu/publication/PP323 has quality photos and descriptions of the different stages of citrus canker, along with photos of other citrus issues.
Stem lesions on grapefruit. Photo by Beth Bolles, UF IFAS Extension Escambia County.
The bad new for homeowners is that there is not a treatment to cure citrus canker. If the infection is small (a few leaves or a branch), it may be possible to remove and dispose of the material, following proper sanitation guidelines. Homeowners may also suppress a small infection on fruit by using copper-based fungicides, applied at appropriate intervals. These fungicides only protect plant tissue for a short time by acting as a barrier to infection. See this UF publication for timing of copper sprays for fruit.
Once susceptible citrus are heavily infected, trees will have fruit and leaf drop, along with general decline and dieback. At this stage of the disease, homeowners should strongly consider removing the tree. If it can be burned on site in accordance with local burn laws, that keeps the material contained and may reduce disease transmission. Otherwise, all material should be double bagged and sent to a landfill. Do not compost any material onsite or at local composting facilities. Be sure to follow disinfecting techniques outlined in the University of Florida publication https://edis.ifas.ufl.edu/publication/PP323 for tools, hands, and clothing.
Since management of citrus canker is so difficult, prevention is the best method to protect your tree. If you are considering a citrus, choose a more resistant selection outlined in the UF publication, Table 2. Always purchase a citrus from a certified nursery and follow state guidelines which prohibits all propagation of citrus, unless registered to do so.