Seeing some of your plants turn brown in the winter can be a bit concerning.
It’s good to know that it’s normal for many plants, such as turfgrasses, to go dormant and turn brown in the winter.
The plant is protecting itself during cold temperatures and lower light levels.
Typically, plants will recover once spring arrives.
However, hard freezes may injure or potentially kill some plants.
The best way to protect your plants from cold injury, or death, is to select plants for your landscape based on the USDA Hardiness Zone Map that outlines which plants are most likely to survive in a given zone (https://planthardiness.ars.usda.gov/PHZMWeb/).
Florida is a wonderful place to grow a wide variety of plants, but not all of them thrive in every part of the state. For instance, a Christmas palm does well in South Florida, but won’t survive the winters in Central Florida.
Also, just a few miles can mean a big difference in temperature variations between our coastal and inland locations.
A principle of Florida-Friendly Landscaping is to plant the right plant in the right place. Not only does that principle apply to location in the landscape; it also applies to your climate zone.
Even though cold damage can cause injury to many plants, don’t lose hope. There are a few considerations to keep in mind to help your plant recover from cold injury.
It’s helpful to know that soils that have frozen even slightly, like in a container, can lose a lot of moisture and cold-damaged plants still need water.
After a freeze, check the soil around injured plants to determine if they are dry or not. If dry, irrigate until the soil is moist, but not wet.
It is tempting to fertilize plants after injury to stimulate new growth, but it’s not a good idea to “tell” an already injured plant to expend energy to grow — especially when the risk of more damage from another freeze is possible.
Resist the urge. Don’t fertilize until later in the season after the plant has shown obvious signs of recovery and is actively growing. That typically happens in late spring or even as late as summer.
The principle of patience also applies to pruning.
Cold-damaged plants typically look terrible with brown and even black, dead tissue. But, pruning tells the plant to grow, so put down the pruners.
Extensive growth during recovery robs the plant of vital energy and nutrients, and leaves new, tender tissue vulnerable to more damage from cold weather. Once the threat of frost or freeze passes, it’s safe to remove dead plant tissue.
If your lawn happens to be the common St. Augustinegrass, and it suffers extensive cold damage — which typically only occurs when exposed to temperatures around 20 degrees Fahrenheit — it will most likely die. Bahiagrass will rebound when warmer weather returns. If the lawn turns brown and stays brown, and appears to rot away, you’ll want to re-sod or re-seed, depending on the turfgrass species, to reestablish the lawn.
Some cold-injured ornamental plants may take years to recover from the roots, such as hibiscus.
Cold protection is relatively simple though. For most ornamental plants in pots, simply move them into a protected area when temperatures below 40 degrees Fahrenheit are predicted.
If the plant is not easily moved, a bed sheet or blanket makes a good cover. Just ensure the cover drapes all the way to the ground so that heat from the ground can be trapped under the cover protecting the plant. Place a rock or brick on the cover to anchor the cover, but don’t allow it to weigh down the plant and cause damage.
Additionally, if you can erect a simple scaffold for the blanket to rest on just above the foliage, there’s less chance of cold injury since frost that rests on the blanket that touches the foliage can still cause damage through heat loss.
Many homeowners “lollipop” the blanket around the trunk or base of the plant cutting off the flow of heat from the soil, so don’t make this major mistake.
Plastic sheeting can be used, in a pinch, but it must be removed before sunlight strikes the plant in the morning or you risk burning the plant underneath, which happens rather quickly.
There are some commercial frost clothes that also can help prevent cold injury, but they must be used in the same way mentioned above.
With any cover, remove it once the temperature is above freezing early in the morning to allow the light to reach the plant, reduce the chance of sun scald, and get more heat into the plant.
Cold damage is not always preventable, but it is possible for plants to recover with a little TLC. In most cases, the plant just needs to be left alone to recover on its own time.
For more information about reestablishing your lawn, go to: https://edis.ifas.ufl.edu/lh013. For more information on cold protection for ornamental plants, refer to: https://edis.ifas.ufl.edu/topic_landscapes_and_cold.
By Whitney C. Elmore
Dr. Whitney C. Elmore is the UF/IFAS Pasco County Extension director and an Urban Horticulture Agent III.
Published March 11, 2020
