Posts Tagged evergreen leaf cold adaptation
Here in the Piedmont region of North Carolina, winter is refusing to relinquish its grip. We’re not buried under feet of snow like our more northern neighbors, but the cold air refuses to head back to the Arctic, and frequent precipitation events teeter between rain and ice, often producing both forms in one episode.
Last Saturday, it snowed all day and into the night, but almost none of it lingered, because the previous day we had soared into the upper 60-degree range. It was fun to watch enormous wet snowflakes fall steadily while the Spring Peepers droned enthusiastically in the adjacent swamp. They didn’t quiet until the sky cleared and the temperatures plunged, turning melted snow into treacherous black ice.
Late winter temperature variations don’t seem to bother salamanders any more than they do Spring Peepers, as demonstrated by the top photo. That’s a salamander egg mass. We’ve observed several species of these amphibians on our property, so I’m guessing when I identify these eggs as those from a Spotted Salamander. I’m going by the description of egg-laying behavior at the link provided. Those black dots are the growing embryos encased by the gelatinous material that protects them until the new-born amphibians are ready to emerge.
Sunday morning after the sun melted icy walks, Wonder Spouse and I wandered up to the vegetable garden to discuss our immediate to-do list preparations for the spring garden. I’ve sowed quite a few (seven, I think) varieties of spring greens in the greenhouse. I’m hoping they’ll be ready for transplanting in mid-March, weather permitting. We have much to do to ready planting beds before that time — if winter will stop covering my garden in ice!
While we were there, we realized our abundant chive plants have begun putting out fresh shoots, despite winter’s persistence.
It’s a good thing that members of the onion family are relatively cold-resistant, don’t you think?
On Sunday night, temperatures plunged into the teens. The National Weather Service’s official recording station at our airport recorded a low of 18 degrees Fahrenheit. The thermometer on our hill got down to 13 degrees. Microclimate differences and the absence of nearby concrete and asphalt heat islands account for our consistently lower temperatures.
Fortunately, native plants are well adapted to our up-and-down temperatures, as evidenced by the native rhododendron (Rhododendron maximum) that grows beside our back deck. This species is common in our mountains, but it does occur naturally in a few places in the Piedmont region, where so-called relict plant communities from the last glacial period survive to present day. I would never have planted this species where it grows in my yard, but it was here when we moved in 23 years ago, easily tripling in size since then, so I don’t argue with it.
Here is what the rhododendron looked like at 7:20 a.m. Monday morning, when our thermometer read 13 degrees:
See how sad the leaves look? The shrub is fine; this is how evergreens adapt to severe cold. They temporarily shut down their leafy water transport mechanism to protect leaves from damage. But the plant does look pitiful, as evidenced by this closer view:
A mere two hours later, the shrub’s protected southern exposure combined with strong sunlight helped the plant recover its composure.
So adept is this plant at its cold-recovery trick that you’d never know how sad it looked two hours earlier.
Such is the nature of Salamander Season here in the Piedmont. One minute, we’re shivering in frigid air, the next, sunlight and Spring Peepers warm us into spring garden dreams.
Friday’s forecast is calling for morning sleet that should morph into cold rain. Although inconvenient, I am grateful for every drop of precipitation. My county remains in moderate drought, a thirsty peninsula surrounded by well-watered counties to our east, north, and west. I will happily delay spring planting for mud-making rain, knowing we need that water to fight summer’s inevitable drought-worsening heat.