The global warming Paul Reveres are all in a tizzy this week. Over half the country is experiencing record cold. Here in Birmingham, we’ve into our fourth straight day of temps that haven’t risen above freezing. I took the photo above are 1 PM yesterday. The guys at our building left the sprinkler system on all night to make sure that dormant plants that received 70 inches of rain last year didn’t dry out. It worked!
We almost never have a day here that stays below freezing. In fact, we haven’t had a cold spell like this since the 1940s. It’s supposed to snow tomorrow and night temps will drop to the single digits over the weekend. That makes trips to my outhouse exercises in efficiency. Something is therefore seriously wrong with the world and portends our imminent doom. I blame genies.
However, in the event that the world doesn’t end quite yet, you may be wondering what effects this most recent blast of global cooling will have of your plants. Will they survive the Big Chill? Will they be crippled for life? The Grump is ready with answers.
Tropical Plants (Chinese hibiscus, croton, tibouchina, etc.) – If you left them outside and the temps got anywhere near freezing (even a light frost), butter them well, because they’re toast. I expect a lot more damage in the Deep South than in the Upper South, because the cold has penetrated all the way to south Florida (in the 40′s in Miami) and plants there have no defense.
Tender Perennials and Shrubs (lantana, Mexican bush sage, angel’s trumpet, cast-iron plant, agave, sago palm, holly fern, Japanese pittosporum, etc.) — These are the plants that never used to make it through the winter, but 15 years of mild winters have lulled us into a false sense of security. Some may be killed outright; some may just be killed to the ground. Insulating the base of a tender plant with several inches of mulch or fallen leaves may bring it back next spring.
Poor Little Daffodils and Other Bulbs — Don’t worry if you see bulb foliage all shriveled and wilted by the cold now. This matters not. When the weather warms in spring, new foliage will emerge and flowering will commence as usual. The only time cold really hurts these bulbs is if it freezes just as new flower buds are opening.
Spring-Flowering Shrubs and Trees (forsythia, quince, azaleas, saucer magnolia, camellia, etc.) — Any flowers that have opened already are deader than justice on Wall Street. However, unless it gets even colder, flower buds that are still tight should be OK. I’m betting that the budding flowers of paperbush (Edgeworthia chrysantha), shown at left, will be OK, because ice is a good insulator for plants. This is why fruit and vegetables farmers spray water on their fields before an expected killing frost. (I don’t recommend this treatment for people, though, with the exception of baseball legend Ted Williams. His head was frozen for posterity. I bet it can still hit .300.)
Cold Is Good
As you’re shivering this week, wondering whether you can make it to Starbucks without getting frostbite (never mind my outhouse), consider how positive cold is for gardening. It makes tulips, azaleas, peonies, apple trees, and other plants that need winter chilling bloom better in the spring. Cold kills off bugs that would otherwise overwinter. Most important of all, cold teaches us how stupid we were to plant things that have no chance of surviving a normal winter.
So while you still can, hug that Norfolk Island pine you stuck outside on the porch. It’ll be the last hug it ever gets.