The notion of invasiveness in native plants is one that is distasteful to contemplate. Usually we prefer to say that a native plant is a “strong spreader” or an “aggressive spreader.” At some point it may be necessary to stop splitting hairs. I’m thinking particularly of cup-plant (Silphium perfoliatum). It first caught my attention when it appeared in a news item as having spread aggressively along a riparian stretch in upper New York state, where it is not native. It had been introduced by a landowner and happily galloped on from there. It is now “potentially invasive” and banned in Connecticut.
In my own yard in southeastern Michigan I introduced it as seed some years ago, oblivious of the fact that it is not native to my own county. It is spreading quite aggressively. Fortunately it grows quite large, is hard to miss, and therefore easy to chop down.
This is a clear example of a native plant that behaves well in its traditional plant community, in its traditional habitat only to become a pest when moved by humans into areas that it might not have moved into on its own.
No-Till, No Problem
A brief article was published recently in the Journal of Environmental Quality relating no-till farming practices and increased emissions of greenhouse gases – most notably nitrous oxide. Since natural landscaping also employs essentially no-till methods it may be a short, though erroneous, leap in logic, in some minds, to connect natural landscaping and increased emissions of greenhouse gases.
It’s important to know the rest of the story: The problem of greenhouse gases arises when fertilizers are spread on top of last year’s crop residue of corn stalks or soy straw, landing several inches above the mineral soil. When the fertilizer is injected several inches below the surface of the soil, greenhouse gas emissions are no longer a problem.
Since natural landscaping does not use fertilizers in any case, it is safe to conclude that gardening methods using minimal soil disturbance will not result in the increased emissions of greenhouse gases.
It’s All One Piece
In the early 1990s deformed frogs with oddly shaped, missing, and extra limbs were discovered in a pond in Minnesota. To date, 40 states have reported similar discoveries, and speculation runs rife as to any causal relationships – exposure to pesticides like Atrazine; exposure to ultraviolet light from the thinning ozone. Pieter Johnson, a researcher at the University of Wisconsin, says his theory is