<Blog post originally posted in 2022, but contains pertinent info on how to treat sensitive plants during an early spring freeze.>
After getting spoiled by unseasonably warm weather the last couple of weeks, we’re in for a rude awakening! You’ve heard her all week long on 95.5 WSB… meteorologist Christina Edwards forecasting a ‘hard freeze’ with a low of around 25 degrees for the Atlanta-area, Saturday night into Sunday early morning. She reminds us that a hard freeze is when temperatures drop below 28 degrees for more than a few hours. So, what to do?!?!
From emails, to texts and Facebook messages, many concerned gardeners have reached out, asking me about protecting anything from blueberries and fruit trees - which are starting to bud out, to daffodils, Carolina jessamine, hydrangeas, camellias, and forsythia.
Let’s start small. First, I’d evaluate what you can bring in on Saturday: potted plants and trees, plants you managed to over-winter, even glass hummingbird feeders that you may have already filled so that they don’t freeze and crack. For larger potted items, do your best to place them so they’re up against the house, shed or carport. That will provide some protection.
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Some general strategies that are easiest and most effective are simply covering the plants that you can. Whether you use frost cloth, sheets, plastic, or even cardboard boxes, all of these will provide short-term protection. Two key things to remember though- 1) make sure the cover goes all the way to the base of the plant. Use rocks, bricks, or anything you have to anchor it down for the night. And 2) remember to remove the covering somewhat early in the day on Sunday. Sun will come right through plastic and can burn a plant. Frost cloth is the only thing where it’s possible to leave it in place for a longer period of time.
The American Hydrangea Society, based here in Atlanta, is even warning folks of this cold blast. Their advice- “Cover plants with sheets and use stakes so the sheet doesn’t rest on the plant and cause breakage.”
The University of Georgia Cooperative Extension has written extensively about protecting fruit crops from late freezes. While things like orchard heaters and wind machines are not standard for the average homeowner, UGA recommends also, simply covering what you’re able. And here’s some good news, given that we have had warm sunny days leading up to this weekend. “Mulches and other coverings will be most effective when the preceding day has been warm and sunny. In addition, most soil retains greater amounts of potential radiant energy, and covering the plants at least an hour before sundown will slow the rate that heat is released from the soil. Mulches and coverings are a passive system for freeze protection and are dependent upon capturing ground heat.”
And unfortunately, some of this is just wait and see. It could take months for us to really observe any lasting effects of this or any other late freeze. In regard to the winter-blooming plants like camellias, Carolina jessamine, and hellebores, they are cold-tolerant, so not much to do there. If you’re enjoying the yellow display of daffodils and in some cases hyacinths that are beginning to bloom, I’d suggest you cut them before Saturday night, and enjoy them in a vase!