Winter's Legacy and Spring Forward

This winter’s cold is most evident on bamboo. Clumps of tawny, dead leaves, still attached to the canes, stare out from among the trunks and stems of dormant trees and shrubs. I hadn’t realized that bamboo was so widely planted. The depth of cold isn’t what killed the canes and leaves; it was the duration of cold. Seventy miles south of here, leaves of yellow groove bamboo, Phyllostachys aureosulcata, among the most cold hardy of the thick-caned bamboos, typically stay green and fresh all winter, but even they’ve been killed.

My bamboo, before pruning

No, the plants aren’t dead; just their canes and leaves. Warm weather will coax new shoots from the roots, shoots that will push skyward rapidly. I’ve measured as much as 6 inches of elongation per day. The record for bamboo growth, not around here, of course, is almost 3 feet in one day!  (That little tidbit comes from Bamboo, by Susanne Lucas, a beautiful, new book -- in its binding, photographs, and clear writing -- that provides an introduction to the culture, horticulture, and myriad uses of bamboo. Read it and you also will want to grow bamboo. For even more in-depth information on bamboo botany, culture, and uses, I turn to the no-frills book, The Book of Bamboo, by David Farrelly. )

Once bamboo shoots stop their skyward ascent, the walls of the canes begin to thicken. Canes that survive winter with green leaves intact don’t grow any taller in subsequent years. Cane diameters remain constant as they thicken within, in so doing becoming more useful for stakes, fencing, gates, and structures in the garden and beyond. Eventually, whether winter temperatures are frigid or mild, a cane dies.

Bamboo, after pruning almost all of it down to the ground

Dead canes, weather from age or from winter cold, eventually need to be removed to keep a grove looking spry. For my planting, I decided on the dramatic approach, cutting virtually the whole planting to the ground.  I used a lopper, attacking canes one at a time, then a machete to remove side shoots with leaves from canes worth saving -- not an easy job but one that yielded an abundance of useful canes. Now, what to do with my stockpile?

------------------------------------------------

As winter freezes have segued into capricious spring frosts, seedlings need to be readied for the great outdoors. In a greenhouse, on a windowsill, or beneath fluorescent lights, these plants lead a coddled life. Outside, life is tougher: temperatures swing 50 degrees in a 24 hour period, winds whip tender leaves, and intense sunlight beats down.

What these plants need is a couple of weeks of acclimatization -- “hardening off.” Not too quickly and not too severely, though, or leaves could burn or flowers could appear prematurely; a plant could even die from shock. The thing to do is to find some cozy spot outdoors for the transplants, a spot that is sheltered from wind and receives sun for only part of the day, or else dappled sun all day. After about a week, the plants are ready to me moved to a more exposed location, one that just takes the edge off gusty winds and broiling sun. A week at this second location and plants are ready to be planted out in their permanent homes.

Seedlings getting ready of the great outdoors

The kinds of changes that hardening off induces in coddled seedlings depends on the nature of the seedlings themselves. Seedlings of cabbage, lettuce, snapdragons, pansies, and other plants that can eventually laugh off cold even below freezing develop a tolerance for cold by building up sugars in their cells. Gradual exposure to more intense light also thickens cell walls, fibers, and cuticles on both existing and new leaves. With increasing light exposure, chloroplasts, the green, light-trapping energy factories in leaves, move around and align themselves in such a way that the leaves turn darker green. And the leaves’ stomatal pores, through which water is lost and carbon dioxide and oxygen are exchanged, become more quickly able to open and close in response to changing conditions.

Cold-tender plants such as tomatoes, marigolds, and zinnias suffer at temperatures even above freezing. With these plants, chilling injury causes changes in plant membranes that interfere with photosynthesis and damaging toxins build up in leaves. Hardening off makes these plants better able to repair and prevent such damage. But temperatures that still drop below freezing mean that it’s still too early to begin hardening off cold-tender plants. Anyway, they’re still too small. Wait a month.

During the two weeks of hardening off any plant, growth slows and the plant becomes stockier. This is good; it indicates that a transplant is ready to face the world.  

Bananas, No, Yes.

Yes, we have no bananas. We do have a banana tree.

Decades ago I was in a similar situation. How could I resist a catalog ad for a dwarf banana tree, one that wouldn’t grow more than 6 to 8 feet high, so could be accommodated within the confines of a standard room? I bought the small pup, which is what small, plantable offshoots from the mother tree are called, and planted it in a large pot. The pup grew. And grew. And grew. The plant topped out at 6 to 8 feet but the developing leaves, rolled up and pointing skyward before unrolling and flopping down, reached a lot higher. Banana isn’t really a tree; it’s a giant herb whose “trunk” is, in fact, made up of concentric layers of rolled up leaves that don’t flop down to a more horizontal position until they unroll.

“A mature tree only gets 6-8 feet tall, but provides up to 90 bananas per year!” states a contemporary web ad for Cavendish dwarf banana. As for the 90 bananas, yes, I had no bananas. Bananas are tropical

plants, thriving best in full sunlight with average annual temperatures around 80°. A sunny room in winter is no home for a banana. The room was cool, not tropical, and, though bright, its light paled against a sunny day in the tropics.

Besides delaying or voiding any possibility of fruiting, indoor conditions left my plant looking forlorn, even if it did perk up each summer outdoors. Upon my return from a winter trip to the tropics where I had seen banana plants reveling in sun, heat, and humidity, I took pity on my Dwarf Cavendish and granted it eternal afterlife in my compost pile.

------------------------------------------------

Last spring, my friend Sara (of last week’s grafted tomato fame) stopped by with a gift: A banana plant, evidently another a Dwarf Cavendish Banana judging from the decorative reddish splotches on the leaves. How could I refuse such a plant, recently removed from a greenhouse, in all its lushness.

In the decades since my old banana’s passing, banana plants have become more popular as ornamentals. The plants grow rapidly, so a non-dwarf variety, once summer heat kicks in, will soar quickly to 10 feet or more to create the focal point of a tropical oasis. You’d need a big pot to fuel such growth. Or you could plant Mekong Giant Banana (Musa itinerans var. xishuangbannaensis) or Golden Lotus Flower (Musella lasiocarpa), both closely related to the edible banana but -- and here’s a big difference -- very winter cold-hardy (for bananas). Either plant (available from www.onegreenworld.com and www.raintree.com) could remain outdoors, with mulch, through winters with temperatures well below zero degrees . The tops die back but the roots survive to resprout each year. Who wants to see a tropical oasis in the snow anyhow?

Dwarf Cavendish is not a hardy banana and does not reach proportions to create anything more than a mini-oasis. Still, my new one is weathering winter well. My original plan was to bring the potted plant down

to remain semi-comatose in the cold basement. But it started out in autumn near a sunny window in a cool room and never made it down the steps. It looks forlorn but ready to perk up after conditions change. And small, because it’s cramped into an undersized pot. I haven’t watered it for months! I don’t want it to grow -- yet.

Come spring, Dwarf Cavendish will get repotted, pups removed and potted, and given good growing conditions. One pup will get planted outdoors to get as big as it can before cold weather, then dug up and put in the basement. Even if “Yes, we have no bananas,” there will be leaves aplenty for cooking, wrapping, serving food, and general tropical lushness.

------------------------------------------------
Not that New York bananas are an impossibility without a old-fashioned, energy-guzzling  hothouse. Given an early start in my barely heated greenhouse, a short-season banana might actually ripen its fruit this far north. A guy in Georgia has found that the variety Veinte Cohol (www.logees.com) will ripen its fruit in October if it’s 2 to 3 feet tall going into summer. My greenhouse is something like Georgia, without the drawl.

------------------------------------------------

All this talk of bananas is admittedly odd with morning temperatures here hovering below zero degrees. This winter has been interesting, seemingly cold but only in comparison with the relatively warm winters of the past decade or so.

The low here, so far, has been minus 14 degrees. The effect is already evident on my bamboo, Phyllostachys aureosulcata, whose leaves, though still attached, are dry and muted green. They were

supposed to remain alive, looking shiny and lush green, down to minus 20°. But the cold came on quickly this season, before plants had a chance to acclimate, and there were extended periods of it. Rainfall, snowfall, and humidity also have direct and indirect effects on how well plants face cold. For plants “it’s not how cold it gets, it’s how it gets cold.”

Bamboo Death(?) and Zucchini Life

Flowering is desirable in some garden plants (fruit trees, broccoli, and, of course, flowers) and undesirable in others (lettuce, cabbage, and arugula). I’m not sure how I feel about the flowers recently appearing on my bamboo (Phyllostachys aureosulcata). Yes, bamboo! Bamboo typically flowers only after decades of growth, sometimes after more than a hundred years of growth. My bamboo is about 25 years  old.

The downside to bamboo flowering is that it weakens, sometimes even kills, the plant. And “the plant” could be a whole grove since bamboo spreads by rhizomes (underground runners). All shoots are connected underground and are, essentially, one and the same plant. Bamboos sometimes flower gregariously, that is,

most or all of them all over the world flower in unison, so death or weakening could be more widespread than my little grove.

Which brings me to what is good about flowering of bamboo: It’s very interesting (but very unspectacular). I’m not too worried about my whole grove dying because I remember starting with a few pieces of bamboo which, perhaps, were not a single clone. Also, lopping off flowering shoots would keep them from draining the rhizomes of energy.

The best thing about the flowering is the possibility of collecting seeds. How exciting. Bamboo from seed. I won’t get my hopes too high because bamboos typically yield very little, in some cases, no seeds. On the other hand, sown in flats, the seeds allegedly sprout within only 3 weeks.

o, does anybody else anywhere have flowers on their Phyllostachys aureosulcata? This species is commonly known as yellow groove bamboo, notable for the vertical, yellow groove on the canes and the bent “knee” often on the lower part of a cane. It’s one of the best bamboos for sturdy canes where winter temperatures plummet below minus 15°F.

------------------------------------------

Searing heat and plenty of rain have made for Amazonian weather here, much to the liking of weeds (even with the “weed less” techniques I use, as described in my book Weedless Gardening). Rains in June were almost 200% higher than the average.

Mostly, what’s involved in weeding here is periodic hand pulling, starting at one end of the garden, then working my way across the garden ripping out main roots and tops of weed plants. I’m spurred on knowing that, for instance, one lamb’s quarter plant can produce over 70,000 seeds, and having noticed the speed with which sharp quackgrass runners spread underground.

I admit to having too much garden, so some neglected areas always get ahead of me. Like that patch of quackgrass growing and spreading happily between a couple of dwarf apple trees. Digging out the quackgrass would be too tedious. Tilling the soil would kill the plants, but many of the chopped up runners would take root and grow into new plants. Tilling would also expose buried weed seeds to light and more air -- just what they need to sprout.

My tack is to mow the plants to the ground and cover the area, and a bit beyond, to account for underground spread of runners, with 4 layers of newspaper, overlapped. An alternative cover is grey resin paper, a building product, available on rolls that make the paper easy to roll out and, therefore, useful for larger areas. The paper smothers weeds in place, leaving the roots and tops to rot and enrich the soil.

Sure, the paper looks ugly and can blow away. That’s why I wet it as soon as it goes down, then cover it with mulch, wood chips, in this case, because I happen to have a pile of wood chips available.

This method of killing weeds is effective, easy, quick, and I can immediately plant something -- a second crop of zucchini transplants is my plan -- in the mulch. As long as everything is kept moist, roots of the transplants can grow into the mulch and then into and down through the wetted paper into the moist earth below.

------------------------------------------

My first crop of zucchini, from transplants seeded in early May, is growing like gangbusters. And it’s no

wonder, given the weather and their being planted right in the compost piles. Nutrients, warmth, and water: What else would a warm-weather plant need?

The compost piles are covered with EPDM rubber roofing material to seal in moisture and heat, and to keep out weed seeds. I cut two square flaps, each about 3 inches square, into the EPDM in which to “plug in” the transplants. The compost, in addition to offering a smorgasbord of nutrients, also clings tenaciously to water, so the zucchini plants need essentially no care.

In contrast, some care will be needed for the zucchini transplants that will go into the mulch between the apple trees. They’re at ground level, just right for rabbits, and the soil there is nowhere near as rich or moisture-retentive as pure compost. Then again, one can have too many zucchinis.