Brian Causey, owner of Exquisite Lawn Care in Celebration, offers information and advice on how to take care of your landscaping in times of extreme cold. Scroll down to read the entire piece – much good information!

Frost 

• can occur at or below 38 degrees
• frost falls straight down.  Trees will block it.  Structures will block it.
• Can damage exterior foliage of plant material
• Not all plant material is susceptible.  Crotons have a cold tolerance around 50 degrees; Roses can be around -20 degrees.  
• Damaged material can be trimmed off and plant material recovery can be quick
• Frost will not settle if it is windy even below 38 degrees.  It was very windy Friday night and there was little to no frost Saturday morning.  There was no wind Saturday night, and the frost was very bad Sunday morning.

Freeze

• Occurs at 32 degrees and lower
• The severity of the freeze depends on the length of time under 32 degrees.  Over 4 hours is considered a hard freeze and is damaging
• It can frost during a freeze
• A freeze occurs underneath a tree canopy, next to a structure, under a frost blanket.  The air is freezing
• Damages to plant material can be more severe, all the way to expiration of the plant itself
• Not all plant material is susceptible.  Crotons have a cold tolerance around 50 degrees; Roses can be around -20 degrees.  
• Damaged material may need to be cut all the way to the root ball

Preparation: When we know a weather event is coming, there are steps we can take for prevention

• Wrapping above ground pipes, well systems, water softeners/ filters with blankets
• Bringing in pets and pots with sensitive plant material easy to transport
• Checking on neighbors
• Remove standing water so it does not create ice or slippery conditions
• Turn off irrigation.  In the North, they blow out the water in the systems because the ground will freeze.  Underground pipes do not freeze here…historically.
• Cover plants.  This is a big one with a lot of misinformation:
  • Frost
    • Know what to cover.  Understand the cold tolerances of your plant material.  It wouldn’t make sense to protect Podocarpus over a Hawaiian Ti.
    • Cover plant material to avoid frost from developing on the leaves on top of the shrub.  It is not necessary to cover the sides.  When have you ever seen frost on the side of a bush?  It is always the top.
    • Do not lay the blankets directly on the plant material, it can pass through depending on the frost protection blanket.  Also, the weight of the frost added to the weight of the blanket can damage fragile material like annuals.
    • Use stakes(wood, metal, pvc) to create a tent above the material
    • Use bricks, staples, or other weighted material to secure the blankets from winds blowing them off
    • Material has to be uncovered during sunlight hours and recovered just before the sun sets.  Leaving the blankets on during the day can sometimes be more damaging than trying to save plants by covering them.
  • Freeze
    • Everything for a frost, with a few changes-
    • SOMETIMES, there is no point to covering during a freeze.  The air is freezing.  A thin sheet is not going to stop it.  Without a heater in our homes, eventually concrete blocks are not enough to keep the cold out.  How long are you able to stand outside in temperatures lower than 32 degrees, in the dark, with wind, in a jacket, before it is too much to bear.  
    • Covering sounds great and looks great but know when to do it.  A lot of people just found this out the hard way by covering material like Hibiscus, Crotons, and Ixora only for it to come out just as bad if it were not covered.
    • If you really wanted to do freeze protection correctly,  you would cover the material like a tent and run a heater inside.  This would require you to stay awake all night, typically done with a team, to monitor so a fire does not break out.
• Do not run irrigation.  Especially in an urban area, this can cause hazardous conditions in areas like sidewalks.  It can also create ice on plants and freeze groundwater close to the root ball damaging the plant material more.  Farms run irrigation to freeze crops.  They are experienced.  They are up all night continuously running water, there is a team of them there.  They are professionals.

Recovery

• First step is monitoring
• Patience is very important.  The knee jerk reaction is to cut everything back to where it is alive.  Relax,  let nature take its course.
• We often do not see full effects from a weather event like this until temperatures rise closer to 80 degrees
• Survey the damages and assess.  Once temperatures are back up, check material again.  Now you can determine the severity of damages.  Scratch the bark and see how far you have to go to hit live material.  That is the point of where to cut back to.
• Do not get taken advantage of.  Do not let anyone tell you your yard is dead.  Check yourself or get another opinion from a professional.  A lot of people are taken advantage of before, during, and after a natural disaster or act of God.  It can be terribly expensive to replace the entire landscape and an unexpected expense.  Try to recover as much or all of the damaged plant material as possible.
• It takes time.  In today’s fast paced environment, everything is expected right now.  If I cut it back to the dirt, how long until my Croton is 4’ tall again???  It is not such an easy answer.  It can take 3 months before you start to see signs of recovery on some material.  It depends how much rain we will get, how quick it warms up in Central Florida.

NOW FOR THE BIG QUESTION

When should I cut damaged material back???  This is a good question, with an almost impossible answer.  We must use a best guess.  Personally, I wait until February 15^th.  At this point, there is a good luck at the 14-day forecast which takes us to the end of February.  While most freezes occur in January, we can still experience them in February.  I cannot remember ever experiencing a freeze in March.  Frost, yes, but not a freeze.  If temperatures look stable, we start cutting back.  This is also the same information I use to determine Crepe Myrtle pruning timing. Although I disagree with pruning them back  (Crepe Murder) we try to do it when the temperature is safe to.  Towards the end of Winter, before Spring blooms.