Why Freeze After Warm Days Are Bad For Landscape

freeze after warm days

Northeast Florida gardeners are rightfully concerned for their lawns and gardens over a freeze after warm days close to Spring. For days the Earth Works Garden Center staff has been busy implementing steps to protect new blooming Spring plant deliveries from cold temperatures. “Plants need to leaf out as early as they can in spring to take full advantage of the growing season,” according to The Conversation. “But this involves pumping water into their developing leaves, which reduces the concentration of sugars, salts and organic compounds in their tissues and removes their winter protection from cold.” Conditions can be worse when a freeze arrives after an unseasonably warm late winter morning versus during mid-Winter. Ignoring the threat of plant damage comes at a high cost so Learn how to protect your plants from the cold snaps and consider this additional information.

What is Plant Hardiness?
The United States Department of Agriculture (USDA) plant hardiness zones are largely based on the minimum temperature a plant can survive. “Where the USDA zones fall short; however, is that they don’t account for other factors,” according to Gardening Know How. “These include freeze dates, freeze-thaw cycles, the effects of snow cover, precipitation, and elevation.”

2022 Late Winter- Early Spring Weather Snapshot
After above-average temperatures in the 70s and 80s the first week of March 2022, an inland freeze is forecast on the morning of Sunday, March 13, one week out from Spring. Besides the higher-than-average temperatures, the morning temperatures had been low. Forecasters attributed the above-average afternoon highs and chilly mornings to a La Nina induced high-pressure bubble in the atmosphere. “This bubble of high pressure is what we experienced in December,” according to News4Jax. “We experienced the fourth warmest December in Jacksonville’s history.” Weeks of above-average temperature were followed by several days of steady rain ahead of this brief late winter freeze.

Effects of Dramatic Temperature Change on Plants
“Plants develop their cold hardiness in stages,” according to McDonald Garden Center in Virginia. “Each new temperature low increases the plant’s ability to survive even colder temps. Maximum hardiness is usually reached in late January and early February and is best achieved by a gradual chilling. The late warmth allowed the plant cell tissue to retain more moisture thus reducing the concentration of salts and chemicals in the cell that act as antifreeze in high concentrations. As a result, the cells freeze and burst and plant death occurs.” That interpretation of a gradual increase in seasonal plant cold hardiness is substantiated by the University of Florida. “When temperatures gradually decrease over time, the plants ability to acclimate to colder temperatures is increased,” according to the University of Florida. “The opposite is true when temperatures suddenly take a dip during the fall, which can cause more damage than the same low temp would in mid to late winter.”

Whether going into or coming out of winter, dramatic temperature changes adversely impact plants. Have you seen and felt the signs of an early Spring in Northeast Florida, including the high pollen levels and a wide variety of early blooming trees and shrubs? “These ‘spring-like’ temperatures often result in many plants and trees breaking dormancy prematurely,” according to Growing A Greener World. “This sudden drop to below freezing can wreak havoc on tender new growth.”

Protective Measures
While the new foliage of shrubs and trees could burn and drop flowers, with a freeze after warm days more severe harm is likely for unprotected warm-season annuals, vegetables, and tropicals. Perennials stand a better chance of recovery.

-Avoid fertilizing lawn turf until after the last freeze. Lawn turf coming out of dormancy could fall back into a slumber, unable to absorb the benefits of fertilization. “If you fertilize your lawn and another frost hits, your grass will go right back into dormancy, and you’ll have a harder time getting it to green up again,” according to Sod Solutions. “This does more harm than good.” Application of slow-release fertilizer in early Spring reduces the risks of damage associated with an unexpectedly late frost.

-If you’ve moved tender plants back outside consider moving them back into protected areas ahead of a freeze after warm days. Cover plants and provide wind protection for those that can’t be brought indoors. The Earth Works Garden Center has freeze cloth available while supplies last.

-Consider Landscaping with Florida Natives that are better acclimated to the climate and require less care and protection.

-Be mindful that low-lying areas tend to be colder and plantings there will have shallower root development and increased risk of freeze damage. Consider booking a landscape design consultation with one of our Earth Works designers.

For comprehensive solutions to your specific lawn, garden, and landscaping need, contact Earth Works of Jacksonville online or at 904-996-0712. Earth Works operates a retail Garden Center/Plant Nursery in Jacksonville and provides landscaping, hardscaping, water features, lawn care service, lawn spraying, and drainage solutions. 
Earth Works proudly serves clients in Northeast Florida, including Jacksonville, Ponte Vedra Beach, Atlantic Beach, Neptune Beach, Jacksonville Beach, Nocatee, St. Johns, Fleming Island, Orange Park, Middleburg, Green Cove Springs, Amelia Island, Fernandina, and St. Augustine.