Freeze Damaged Plants – When Should I prune away the Damage?
This past week, we experienced a ‘Hard Freeze’ on campus which damaged a lot of our ornamental plants in the landscape. A Hard Freeze is when temperatures are 28 degrees or less for at least three hours, as defined by the National Oceanic and Atmospheric Administration (NOAA). Below freezing temperatures can burn, wilt or completely kill many plants that occur in tropical or sub-tropical landscapes. The central Florida climate zone is listed as Humid Subtropical by the USDA and is in Zone 9B on the USDA Plant Hardiness Zone Map. This zone typically has warm to hot summers and mild winters but can experience below freezing events. The lowest recorded temperature for the Orlando area is 19 degrees on January 1985.
Many plants on campus were impacted by the hard freeze and have minor to extensive damage. It is important to leave the damaged plants alone until the danger of additional freezing temperatures has passed. Pruning away the damage too early, will often trigger the plant to produce new growth during a warming period that can then be more susceptible to another freezing event.