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Disease & Smelly Plants

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You perhaps missed last summer’s plant plague, which might be back this summer. My garden was spared because last summer I happened not to have planted the particular host plant: impatiens (Impatiens walleriana), that workhorse of the shade garden, one of the few brightly colored flowers that thrive with little sunlight. 
Downy mildew disease was the cause of last summer’s plague, which descended on impatiens throughout much of the northeast and parts of the rest of the country. Leaves of infected plants turn pale green at first, then develop downy, white growth on their undersides, and finally collapse. Stems also can eventually pick up infection. Needless to say, infected plants flower little or not at all.
Impatiens in Puerto Rico rainforest, El Yunque
But let’s look forward rather than wallowing in the past. Downy mildew can be expected this year wherever it reared its ugly head last year. Same goes for next year, and the year after, and . . . the spores survive for years in the soil. Downy mildew might even show up where it wasn’t last year, coming in on infected seedlings (early stages of infection are not very obvious) or on spores which, under good conditions, can travel hundreds of miles.
Downy mildew thrives under cool, wet conditions, so the very least that can be done would be to keep fingers crossed and hope for the best. Even better: avoid watering impatiens late in the day or in the evening, and thoroughly clean up everything at the end of the season. Better still: Grow your own plants from seed and/or grow New Guinea impatiens (I. hawkeri), a resistant species parading under such trade names as Fanfare, Divine, Celebration, Celebrette, and Sunpatiens.
The surest bet against downy mildew of impatiens is to not grow the plant. Not being able to grow brightly colored flowers in the shade need not leaves these areas dark and lugubrious. Consider plants with brightly colored leaves, such as caladium, begonia (which also has flowers), and coleus.
By the way, impatiens downy mildew is caused by a different organism than the ones that cause downy mildew on sunflowers, zinnias, and some other plants, so no need to worry about the disease spreading from or to these plants.
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P.U.! What an olfactory “good morning” from amorphophallus, about which I wrote a few weeks ago. At that time, a flower stalk was pushing forth from the top of the bare bulb sitting, soil-less, on a plate. Today, the stalk, 18 inches from tip to toe, finally unfolded its skirt-like spathe up the center of which rose the long, fleshy spadix on which the tiny flowers sit. The whole thing is very eerie and interesting but not particularly pretty.
Having grown the plant decades ago, I knew what to expect, nose-wise, from the plant in flower. So I’ve kept a close eye on it and today my nose trumped my eyes. My remembrance was the plant having the aroma of rotting meat. Todays flower was more reminiscent of a horse barn, but perhaps the plant was just gearing up for its full olfactory show. I took some quick photos, then lopped off the flower stalk and tossed it out the back door. Even my dog Scooter showed little interest in the smelly stalk, the aroma of which is meant to attract carrion insects.
Hugo de Vries and amorphophallus, 1937
About 200 species exist of Amorphophallus, the largest being A. titanum, whose flower stalk can soar to 8 feet high and whose spathe is the size of a small bathtub. This species caused quite a stir back in 1937 when a bulb at the New York Botanical Garden, after growing only leaves for a few years, finally flowered. A photo in the New York Times showed the great botanist Hugo de Vries perched next to the enormous flower. How did he stand the smell?
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Anyone who thinks gardening is tough, what with weeds, insect pests, and diseases, should feel for the Helvenstons, who garden in Orlando, Florida. Not that they have more pests there than we have here, but they have a different kind of pest, city ordinances. Orlando’s ordinances dictate sizes (25% of front yard area), heights, setbacks, and other aesthetics of front yard vegetable gardens but nothing — and here’s the clincher — about water or pesticide use, both of which have environmental repercussions. The Helvenstons’ vegetable garden takes up — no, makes optimum use of — their whole front yard.
If the Helvenstons fail to comply with the ordinances, which at present are recommendations and have to go to the city council for vote, they could face fines of $500 per day. “Our Patriot Garden pays for all of its costs in healthy food and lifestyle while having the lowest possible carbon footprint.  It supplies valuable food while being attractive”, says Jason Helvenston.  “They will take our house before they take our Patriot Garden.”

The fight for the right to grow vegetables — or lawn or ornamentals or whatever you want — on your own property has gone national. To join the fight, or for more information, visit the website www.patriot-gardens.com. 

Let It Be?

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“Let it be, let it be” went the old Beatles’ lyric, and this could very well be a mantra in gardening. Sometimes, sometimes a little, and sometimes not at all.
Take, for instance, the climbing hydrangea cloaking the north wall of my brick house. Even now, bereft of leaves and flowers, the finger-thick vines, with their papery peeling, tan bark are a pretty sight weaving their way across and up the russet red wall. Come spring and through summer, bricks peek out from behind a cloak of heart-shaped, glossy green leaves. In summer, white flowers open on short, horizontal stems that reach out from the wall, the whole effect, with the leafy background, like twinkling stars against a dark sky.
I planted the vine about 7 years ago, knowing that it’s slow to get started and that it can coexist with trees or brick walls, damaging neither. My plan with this vine has been to “let it be” although I did wonder what might happen once stems reached roof eaves and corners of the wall. Now I know: A couple of years ago, stems began to reach around the two corners to start their journey to the other house walls and initially thin stems also began to work their way beneath roof fascia.
The house would look cool thoroughly enveloped in this beautiful, ever-expanding vine, but could the structure handle it? I drew the line, with pruning shears, loppers, extension shears, and ladder, at roof eaves, wall corners, and windows (also threatened), lopping or breaking off errant stems. Climbing hydrangea is just too pretty to remove completely. I can “let it be,” but not too freely.
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For the past few weeks, Whenever I sit down to eat I also give an occasional, worried glance at the bare bulb sitting on a plate at the far end of the table. A pointy shoot a couple of inches long pokes out its top. Has it grown longer?
I’m wary because I had this plant once before, decades ago. I knew I could “let it be.” The bulb doesn’t need to be planted! Even without soil, the shoot will stretch upward and then an eerie purple “flower” will unfurl, much like an upside down skirt. Up the center of the flower will rise a long, pointed, purple stalk (which is actually a spadix on which are the true flowers). So far, so good.
The problem is that Amorphophallus, the botanical genus of this plant, is pollinated by carrion insects, and the fully open flower attracts its pollinators by reeking of dead flesh. To spare my very sensitive nose, I have to stand ready to cover the plant’s head in a plastic bag and whisk it down to the basement at the first hint of carrion-ness, just like I did with the plant I had decades ago. Or just lop the head off.
I accepted a recent offer of this plant, which multiplies readily, because it’s so interesting and so attractive, sort of. Once the bulb calms down from flowering, it does need soil, either in the ground in spring or in a pot. Then comes a leaf stalk, pale, olive-green with dark-brown splotches. When the snake-like stalk reaches a couple of feet in height, a single leaf unfurls into three leaflets that spread out like spokes of a wheel. At this stage, the plant is quite attractive and still eerie. 
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Last night at dinner, as I was eyeing Amorphophallus, I was enjoying a fresh, very, very local salad; the ingredients travelled 75 feet, from my greenhouse. A welcome crunch to these fall and winter salads is fresh celery.
Celery is not the easiest vegetable to grow. The tiny seeds germinate slowly and take a long time to mature into succulent, crunchy stalks. And then, for best eating the plant topnotch growing conditions: cool, moist soil rich in nutrients and organic matter.
Celery may be difficult, but I can just “let it be.” I don’t even have to plant celery anymore. This winter’s stalks, seedlings from last winter’s stalks, will go to seed as summer approaches. The four to five foot seedstalks will mature in midsummer, then bow their seed-laden heads over and drop seeds to continue the cycle. Seeds sprout late each summer, seedlings thrive in cooling temperatures of autumn, and by early winter — that is, now — I have plenty of mature celery that will grow slowly to keep me in stalks until spring. “Let it be, let it be.”
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