|
Nutgrass
By Melanie Devore
There are two extreme behaviors exhibited by property owners. Most of us fit somewhere between the laissez-faire lawn stylist and the possessed property perfectionist. You have seen both in your neighborhood. The laissez-faire types have yards with carpets of vines draping their chain-linked fences. The house may or may not be visible from the veil of "hedges" overtaking the front of the residence. One look at the lawn reveals a diversity of disorderly flowering plants and grass. In contrast, the possessed property perfectionists would never permit a single, creeping botanical invader to gain a stronghold on their fence. Hedges must be pruned precisely to insure the exact, desired shape and height are maintained. The most definitive characteristic of the property perfectionist is the lawn consisting of a single species of grass. It is crucial that the lawn is cut so level that it rivals the immaculate greens of the local country club's golf course. In O'Connor's "A Circle in the Fire," it's as clear as the Queen's gin that the character Mrs. Cope is a possessed property perfectionist.
Mrs. Cope is possessive of her dairy farm in a way similar to a mockingbird that dive-bombs trespassers in its territory. And just like the mockingbird, who will challenge a cat, dog, or human bigger than itself, Mrs. Cope manages to throw down the gauntlet and challenge uninvited guests more formidable than she is. Yes, I am referring to Powell Boyd, W.T. Harper, and Garfield Smith, the three transient youths that take root on the Cope farm. However, the most sinister trespasser on the premises just might be the perennial nutgrass Mrs.Cope constantly battles.
Weeds are trespassers taking root where we don't want them. The term "weed" is not strictly determined by the biology of the plant since human value dictates where we want a particular plant. The most unwanted plant in the world, according to Holm, Plucknett, Pancho and J.P. Herbeger's 1977 "The World's Worst Weeds," is nutgrass. Nutgrasses are not true grasses, and like papyrus, are members of the sedge family (Cyperaceae). Flannery O'Connor's description of nutgrass as an evil delivered directly by the devil to destroy Mrs. Cope's farm is perfectly supported by the observations of weed specialists throughout the world.
When O'Connor described "nutgrass," she could have been referring to either purple or yellow nutgrass, or a mixed population of both species. Purple nutgrass (Cyperus rotundus) is limited in distribution to the southern U.S., while yellow nutgrass (Cyperus esculentus) is found in all states. Purple nutgrass has looser clusters of flowers that rarely, if ever, produce seeds. In contrast, yellow nutgrass has tighter, almost spherical, bottlebrush-like clusters of flowers that set seed. The two species can also be distinguished based on their leaves. Purple nutgrass leaves have wider tips that are distinctly different from the more needle-like tips present on the leaves of yellow nutgrass. When it comes to a head-to-head, or rather leaf-to-leaf competition, purple nutgrass will always emerge the victor.
One reason purple nutgrass is the superior competitor is because of its extraordinary ability to reproduce vegetatively. Many of the plants, ranging from the bananas you had on your cereal this morning to the flag iris colony gracing the lawn of Andalusia, reproduce asexually and not primarily by seed. Purple nutgrass seldom reproduces by seed and does just fine by shuffling its genetic variation on rare occasions. The rest of the time it assaults the lawn using asexual means of reproduction. Underground stems of nutgrass, called rhizomes, not only spread horizontally, but also grow upward and downward. Rhizomes that extend upward form tubers at the surface. In time, these tubers will develop aerial shoots, roots, and new rhizomes. Rhizomes growing downward or horizontal produce tubers in chains. Chains of new nutgrass shoots spring from these tubers to form nearly perfect, linear armies of new plants. Anyone who has tried to establish a new lawn in central Georgia has observed the scrimmage between the their beloved grass and the invading strings of nutgrass.
Purple nutgrass also wages chemical warfare against neighboring plants. Tubers of purple nutgrass produce phenolic acids that effectively deter the growth of surrounding plants. Phenolic acids also may contribute to the unpalatable taste of purple nutgrass tubers. Unlike yellow nutgrass, which has been cultivated as a food source, purple nutgrass tubers taste terrible. Purple nutgrass tubers may never appear in the produce section of your favorite grocery store, but they may make their presence known in the pharmacy in the future.
Besides phenolic acids, purple nutgrass tubers contain terpenoid compounds that possess fever and pain reducing effects. Chemists can examine the structure of these compounds found in plants like nutgrass and figure out a way to generate similar compounds, with the same properties, on a large industrial scale. Sometimes these synthetic compounds survive the gauntlet of tests and approvals to become the active ingredients in drugs. In most cases, they do not. In the case of purple nutgrass, we still await a verdict regarding its potential in the pharmaceutical industry.
The guilty verdict convicting nutgrass for trespassing on our lawns and farm fields has been rendered as clearly as Mrs. Cope passed judgment on her three, uninvited guests as “bad” seed. But unlike the three youths, who assaulted her farm with fire, nutgrass, by seedless reproduction and chemical manufacturing, chided her and assaulted her land in a more covert fashion. Fields can recover from fire. But once nutgrass claims your lawn, you will be fighting an uphill battle for years to come.
|
