The Cold Facts on the Freeze
By Paul James
First, the good news. The vast majority of landscape plants will weather the weather unscathed, despite the brutal cold this week. After all, most are completely dormant and hardy enough to withstand temps at or below zero. In other words, at least 99% of your plants will be fine. Now let’s talk about the 1%.
Trees and Shrubs
Some early spring-flowering trees such as saucer Magnolias started producing flower buds last week, and those buds will get nipped. The same may well be true of Forsythia, quince, and quite possibly, some Hydrangeas. The plants themselves, however, should be fine.
I’ve also seen leaf buds swelling on numerous maples such as ‘October Glory,’ and those buds will take a hit as well. But thankfully, those same trees produce secondary leaf buds that will emerge a few weeks later than usual.
Plants that are on the edge of hardiness — Italian Cypress, Aucuba, Gardenia, and variegated Privet come to mind (and maybe Mimosa) — may not fare so well. Time will tell.
The top growth of Crape Myrtles could take a hit as well, resulting in dieback of their branches. But their root balls are hardy and they’ll bounce back with new growth from their bases in spring. Loropetalum will likely suffer the same consequences. And sadly, the top growth of figs will almost certainly die back to the ground.
Boxwoods and other broad-leaved evergreens may suffer from tip burn, especially if they were pruned or fertilized late last year and new growth never had a chance to harden off completely. The damaged foliage can be removed in early spring.
Plants in pots, even the hardiest among them, are especially vulnerable because they’re more exposed, and that increases the likelihood of their roots freezing solid. (When water freezes around plant cells, that’s okay. But when water within the cells freezes, that’s bad news.) You can move them into the garage, or just plan on replanting in spring.
Daffodils, crocuses, and grape hyacinths started emerging several days ago in my garden, but I’m not worried. Their leaves may turn brown, but their flowers are fine and will bloom on que in the weeks to come.
So, in Conclusion
Unfortunately, there’s not much that you can do to protect your landscape plants when temps drop near or below zero. After all, blankets only provide a few degrees of protection, so don’t even bother trying to cover your plants. And there’s no need to water the top growth to create an insulating layer of ice because thankfully the ice — and in many areas snow as well — is already there.
And there’s a good deal of soil moisture in the ground, which is a good thing, especially in the case of conifers and evergreens, because wet soils hold more heat than dry soils. So cross your fingers, hope for the best, and let’s all wait to see what happens.
One final note: Wind chills have no effect on plants. That’s a measure of how cold it feels to the exposed skin of humans.
Happy gardening, ya’ll. Stay warm.
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