These cold snaps can be killers, but there are ways you can cheat death

When the freeze of January 1977 occurred, I was attending night school while working during the day at Parrot Jungle. One evening during my plant physiology class, I overheard two students exclaiming that the Parrot Jungle would have to close because the garden had been wiped out by the freeze a week earlier.

I had been wondering about that myself because I had seen the damage firsthand. About 15 feet of the canopy of the giant banyan tree had been killed by frost. Giant Areca palms with trunks reaching 30 feet had been killed to the ground. I still remember that morning vividly, the owner and staff frantically running around with hoses and sprinklers trying to protect all of the tender plants by encasing then in ice. It was quite beautiful, long icicles were hanging off full-grown banana plants. The hibiscus and crotons were encased in ice. A lot of these plants did die.

Over the next two decades, I learned quite a bit about protecting plants from cold weather. During those years, we would experience temperatures briefly dropping into the high 20s before sunrise about two or three times a year -- nothing more. By the 1990s I even stopped putting out sprinklers on the grass and just started painting the burned grass with green paint the day after a freeze. In a couple of weeks the guys would cut the grass and no one would notice the difference.

When we started a composting operation in the late 1980s, I noticed that on cold days our pile of compost was quite warm compared to the ambient temperature. The same for the mulch piles. This I learned was the result of biological activity, all those tiny organisms produced quite a bit of heat as they went about their business of decomposing the organic material or eating each other. So we started to take advantage of that process.

In the winter, we began to mulch heavily around all of our more tender plant material like heliconias and bananas, so that the roots and the rhizomes would not be damaged by cold. We could lose the stems and foliage but the plants would grow right back because underground they had been protected by the heat from the biological activity.

Since heat flows from the object with the higher temperature to the object with the lower one, we took this process one step further. I had noticed that the same plant species planted in a container and in the ground would react differently to cold. Potted plants got cold much faster, resulting in greater damage. We started burying some potted plants in beds of mulch for the winter with good results. I also found that when irrigating the ground beneath plants the afternoon before a cold spell, the ground would remain much warmer and less plant damage would result.

So now it has been almost 20 years since we’ve experienced a severe cold spell. At Jungle Island I was growing lots of ultra-tropical plants. We had a beautiful breadfruit tree, Artocarpus altilis, that had been growing in the ground for the past three winters. It had reached 20 feet and had flowered for the first time the week we got temperatures in the high 30s.

I’m using the past tense because I had to cut the tree down to the ground a couple of weeks ago. It was dead from the cold. The red sealing wax palm, Cyrtostachys renda, growing in a large container in our jungle river, has survived. We cover it with a burlap tent when temperatures get into the 50s. One night we left it uncovered and all the older foliage burned, but it is surviving. This is a stunning palm from Malaysia but very sensitive to the cold.

Now our cold-preparation practices are paying off. Except for some of the more cold-sensitive tropicals, our landscape has escaped major damage during recent chills. This I attribute to the judicious use of mulch and compost in the landscape over the past few years, irrigating well before the cold fronts, and not fertilizing so the plants do not have any tender new foliage to burn.

You can see a difference at the park. Compare the stands of the corn plant, Dracaena fragrans. Some stands are burned more than others. I believe this is the result of soil moisture. The corn plants grown on slopes or areas that received less irrigation have more burned foliage.

The palm Carpentaria acuminata is another excellent example. They look great at the park. Usually this time of year they look so burned and beat up from the wind that you want to cut them down.

I’ve also noticed something else of significance: no fig whitefly and no iguanas. Maybe the cold is sometimes a good thing.

Jeff Shimonski is an ISA-certified municipal arborist, director of horticulture at Jungle Island, and principal of Tropical Designs of Florida. Contact him at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

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