Sunday, March 16, 2014

Winter Windburn 2014

The cherry laurels in my neighborhood are not looking good. Chinese Euonymus and Japanese Aucubas are a bit haggard also. Where they come from, this sort of thing just doesn’t happen. And you know the sort of thing I’m talking about: extreme cold followed by snow followed by blustery days and nights. Prunus laurocerasus comes from parts of southwest Asia that enjoy hot, dry summers and mild, relatively rainy winters. Euonymus kiautschovicus (Manhattan Euonymus) hails from eastern China, where winter temperatures generally hover around 40°F.  So there was never a need for them to develop the techniques that keep our own broadleaf evergreens fit for spring.

Rhododendrons, for example, reliably roll their leaves into cigars when the temperatures dip into the low 20s F. Their pores are located on the bottoms of the leaves and the curling mechanism protects these vulnerable undersides. It also allows them to conveniently shed any leaf-loads of ice and snow. You can tell the temperature just by watching the rhododendrons; when it warms up to about 32° again the leaves flatten, no harm done. Wouldn’t it be dandy (or should I say handy) if our own bodies had a similar maintenance system?
You can tell the temperature by the rolling of rhododendron leaves.
But no, we are more like the cherry laurel and the Manhattan euonymus. When water evaporates from these broadleaf evergreen leaves faster than their roots can replace it—which tends to happen when the ground is frozen solid—cells die. Leaves turn brown. Plants turn ugly. It’s their version of human frostbite.
Our response to those same cold temperatures starts with the narrowing of blood vessels in exposed body parts. If this goes on long enough, blood flow to extremities drops and tissue dies, fingers and toes and nose tips being, relatively speaking, expendable.

Of course we have mittens and boots and down-filled jackets, and in fact we can make use of this bundling up concept to protect our tender visitors from rude extremes of weather. We can swaddle them in burlap or spray them with an antidessicant or, like the Staten Island Italians used to do to harbor their figs, build linoleum towers.

We could also choose to plant only natives that are adapted to the weather, but this feels rather hypocritical. We go to extreme trouble to make all kinds of adaptations to our living conditions for the benefit of our fingers and toes (like extracting stuff from 10,000 feet below the soil). It seems only fair to make the habitat suitable for our guests when things turn nasty.
The good thing is, the ugliness of cherry laurels is only spring-deep. Unlike our cold-blasted extremities, their damaged parts were destined to fall anyway, eventually, and will be replaced with fresh new functioning parts. 
How convenient for them.

No comments:

Post a Comment