When we were children, my sister and I used to scour the ground under the huge maple trees in our yard every spring. This ritual was as much a part of our annual rite of passage into spring as sloshing through the puddles on our gravel road or floating pieces of fallen branches down the waterway into the farm pond.
Under the maples we would stuff the pockets of our hooded sweat shirts with the papery-coated seeds that had fallen throughout autumn and winter. “Helicopters,” we called them, because if you lifted them into the air and then released them, they would spin their way to the ground like the blade on a helicopter. Through the back yard we would fly them, past my mother’s flower bed, down into the pasture. We were blind to the rest of the spring landscape, letting the seeds loose hither and yon.
The helicopters provided what must have been hours of endless fascination. How far could we get them to fly? How long would they stay in the air? Where would they land if a breeze came and made them drift away?
Years later, sitting in an ecology class, I struggled to resist the temptation to call out “helicopters” when the professor asked for an example of seed that dispersed by the wind. “Maple, sir,” I should have said with all the scientific certainty I could muster. “Acersaccharum to be specific.” I couldn’t bring myself to do it, though. I was busy calling to mind an image of my mother looking over her iris bed, disturbed at the maple saplings growing up through the sword-shaped leaves. “Oops,” I thought, glad to be too far from home to act on a tinge of guilt that caused me to consider confessing as to how those seeds might have landed there.
Actually, understanding the role of wind in seed dispersal and the evolutionary adaptations of seed made those questions we pondered as children even more fascinating and pertinent. Maple trees – indeed a vast number of plants – rely on seed dispersal as a main component of the survival strategy of their species. The spreading of seed to varied sites helps perpetuate survival of many plants. Sailing on the wind, seed is carried to poor and rich soil alike. Some seeds germinate and grow to maturity, others do not.
If a parent plant simply dropped its seed to the ground, chances are many offspring would be crowded or shaded out. If the devastation of insects or disease hit one, it would likely affect all. The random dispersal of seed to some extent evens the level of risk for the parent plant that its offspring will survive. The wind carries seed to diverse areas, ever so slowly improving the ecological adaptations of the species.
I suppose the jury is out on whether or not wind is the gardener’s friend. The same wind that carries the seed of maples to places far and wide carries dandelion seed to our yards and gardens. It sprays milkweed seed through farmers’ fields. It creates weeds out of naturalized plants.
In addition to the weed factor, we have the dehydration factor to consider. The drying effect of a slow, steady wind across the landscape in a typical spring might be considered beneficial. The movement of air over wet ground increases the rate of evaporation of water from the soil, drying out low-lying, wet areas and speeding our return to cultivating the garden soil.
Yet, wind is not so beneficial once plants get established. The wicking away of moisture from the soil can be slowed by the use of mulch. A layer of mulch slows the evaporation of water from the soil by increasing the pathway between the wicking action of the wind and sun and the precious water in the soil.
In addition to increasing the effects of drought, the wind can be a detriment to our tall, stately plants. To the serious perennial gardener, few sights are as sad as a fallen delphinium after a summer rain and windstorm.
The yard at my home has only a few large trees close to the house. There are no maples, so my children don’t have the pleasure of flying “helicopters” in spring. They resort to floating pine cones through the culvert that crosses the road, down a waterway they affectionately call “Bug Creek.” Who knows, maybe they are dispersing pines to places down creek.
No iris beds there, thankfully!
Diana George Chapin is the NEWS garden columnist. Send horticulture questions to Gardening Questions, RR1, Box 2120, Montville 04941, or e-mail them to dianagc@midcoast.com. Selected questions will be answered in future columns. Include name, address and telephone number.
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