Cold Damage to Palms and Warm Season Turf
Horticulture Extension Faculty
Florida is typically known for its warm winters. But this year’s winter was not typical and has sparked some concerns about damage to palm and turf grasses in our area. Drs. Monica Elliott, Tim Broschat, and Laurie Trenholm from the University of Florida/IFAS Extension provide the following information on palms and turf.
Cold damage to Robellini palm Photo Credits: Ft. Lauderdale REC
Do not remove leaves that have any green color showing. Leave brown leaves until later in the year. The leaves may help to protect the palm from future cold weather. When the palm has produced new growth (2 to 3 new leaves) remove the brown, damaged leaves. Remember: Patience is essential with cold-damaged palms! In the winter of 1989-90’, I recommended to a client not to remove a number of palms from a planting site, but to wait until June or July. They pulled out the palms anyway, and took them to the landfill. In June there was a pile of perfectly good palms all in leaf.
It is important to protect the bud located in the crown of the plant since all new leaves develop from the bud. Leaf bases naturally provide insulating protection to the bud. This natural protection is one reason not to over trim palms at any time of the year.
As warmer weather returns, primary or secondary plant pathogens often attack stressed plants through the cold damaged tissue. Copper fungicides are recommended as an attempt (not a guarantee) to protect the bud and developing leaves from diseases that may attack damaged leaf tissue. The goal of a copper fungicide is to prevent this spear rot from developing into a bud rot that kills the bud, and then the palm.
If the spear leaf does rot and can be easily pulled from the bud, it should be removed immediately, followed by a copper fungicide spray or drench of the bud region, which is now exposed.
Warm-season turfgrasses such as centipede and St Augustine grass are often injured when temperatures drop below 20°F. Damage from freezes can be attributed to poor cultural practices which weaken grass and make it more susceptible to injury or death from low temperatures. Damage may also result from walking on frozen turf.
To see if your lawn has been damaged, take several 4 to 5 inch diameter plugs from suspected areas and place them in a warm area for regrowth. Check the plugs for 30 days or until growth resumes. If good regrowth occurs, then little damage has occurred. If regrowth is absent or sporadic, then some degree of damage has occurred.
To help prevent damage from cold temperatures follow these cultural practices: 1) Don’t apply fertilizer after mid September. Late fertilization promotes shoot growth which depletes carbohydrate reserves and produces new, tender shoots. The new growth is not as tolerant of cold temperatures. 2) Apply ½ to 1 lb. per 1000 sq ft of Potassium in the fall to promote cold tolerance and promote earlier spring greenup of grass. 3) Increase mowing height. This will produce a deeper root system and create a warmer micro-environment due to extra canopy cover provided by longer leaf tissue. 4) Watering the lawn correctly will reduce stress. As the grass goes dormant, less water is needed.
Source: Additional Comments Regarding Cold Damage to Palms, email form Drs Monica Elliott and Timothy Broschat, UF/IFAS-Fort Lauderdale Research and Education Center, January 31, 2010. Fact Sheet ENH-80, L.E. Trenholm, Assistant Professor, Extension Turfgrass Specialist, Environmental Horticulture Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL. First published: May 1991. Revised: May 2000.