Louis Raymond experiments in his own gardens like

a mad scientist, searching out plants that most people have

never seen before & figuring out how to make them perform.- The Boston Globe

…Louis Raymond ensures that trees can grow in Brooklyn…

or just about any other place where concrete consumes

the dirt and skyscrapers shield the sunshine.- USA Today

 
 

NEW Trips to Take!

Myrtle's easy when the conditions are right.

 
 
 
 

NEW Plants to Try!

Louis tries to capture the exact words to describe the fleeting but deep pleasures to be found in these Summer-into-Autumn incredibles.

 
 
 
 

New Gardening to Do!

Allergic to bees? You can still have an exciting garden, full of flowers and color and wildlife.

 
 
 
 

Plant Profiles

Today in the Garden of a Lifetime: Big-leaved Bamboo

indocalamus-tessellatus-hand-012313-640

 

In Summer and Fall, the foliage of big-leaf bamboo—the largest of any bamboo, tender or hardy, big or small, young or old—looks lush and tropical. Today's temperatures are single-digit, and they'll be even slimmer tonight and tomorrow. They are the worst Winter can bring, and yet the big-leaf bamboo looks just the same: Lush and tropical.

 

How can foliage of Indocalamus tessallatus persist in such good shape through such a deep freeze? That's the easy question to answer: All evergreen foliage survives sub-freezing temperatures by reducing its amount of water, and reducing it so much that there're too few water molecules, compared to all the other stuff in the leaf—the structural components of the leaf, the carbohydrates, the amino acids, the chlorophyll—to glom together and freeze. All that other stuff gets in the way of formation of ice crystals; for the purposes of Winter survival, it's just so much antifreeze.

 

The next question is the puzzle. How could the retention of enormous green foliage be a wise strategy for any plant hoping to survive until warm weather returns?

 

Most really-hardy evergreens are conifers, whose leaves have comparatively little internal volume compared to their surface area. (Think about pine needle: It has very little internal space, and that space is all extremely near the outer surface of the needle.) You'd think that having all that external surface so close to the internal volume of the needle would make it less Winter-proof, not more. Wouldn't any remaining water be evaporated or, literally, blown right out of the thin needle by high winds? It turns out that the high proportion of surface area to internal volume is a plus: Surface area must mean surface structure, the rigid and freeze-proof walls and "I-beams" of the leaf that enable it to hold its shape, and prevent damage from high winds. The minimal internal volume is "antifreezed" by being suffused with oils—the fragrant resins so typical of conifers. And the outer surface of the needle has a waxy coating, the cuticle, that stops evaporation due to high wind. (Yes, the needles also have "breathing holes"—stomata—but they close in cold weather.)

 

But the leaves of big-leaf bamboo are huge—up to two feet long and four inches wide—and would seem to have none of the advantages of the pine needles. No problem: Bamboo foliage has other strategies, and even other goals. It is peculiarly rigid, just like bamboo canes themselves, because it has a high proportion of silica, a compound the bamboo forms as it absorbs the element silicon through its roots. Silica makes the fibers of the bamboo flexible yet extremely strong. The foliage, as well. High wind, heavy ice or snow? They are all unable to penetrate or even damage the bamboo's leaves or canes.

 

The bamboo leaves also reduce their proportion of water, as well, achieving still more resistance to freezing.

 

But these helpful "winterizings" aren't the real answer to the survival of the huge bamboo leaves. Bizarrely, that survival isn't much of a goal at all. It's accidental. Regardless of whether this current crop of foliage and canes survives the Winter, the bamboo colony will send up a fresh crop of canes in Spring. The vigor of that new crop doesn't depend on the longevity of the current crop. Bamboo lives by a motto that's the title of the famous novel of Milan Kundera: "Life is Elsewhere." It doesn't matter how horrible the Winter is for the colony's above-ground growth; as long as the underground portion—the rhizomes—isn't frozen too severely, the colony will survive unimpeded.

 

From the bamboo's perspective, then, who cares how—or even whether—that lush and tropical-looking foliage gets through the Winter? It's irrelevant. Only evergreen-hungry gardeners appreciate the accidental persistance of the foliage, even after many weeks of snows and deep-freezes. 

 

By February and March, the foliage's endurance will have becomes exhausted. The leaves' ability to retain even the modest amount of water needed to keep the chlorophyll green will have been decreased and degraded. The tips of the leaves are already showing a bit of wear and tear; by March, they will be largely tawny.

 

Any time the look of the foliage becomes too tattered—and the weather is mild enough to work outside, or I just want to be outside all bundled up—I can cut the canes to the ground without worrying that the bamboo colony is being depleted or diminished by their absence. They were already unimportant to the colony back in December. The show of evergreenity since then has been a gift. An inadvertent one, true.

 

Here's how to grow big-leaved bamboo.

 
 
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