   Noxious Weeds - May 5, 1999 Jeff Schalau, County Director, Agent, Agriculture & Natural Resources Arizona Cooperative Extension, Yavapai County Weeds are definitely an inconvenience in home gardens. This is especially true if you have only been gardening in an area for a short time. Once the area is tamed (cultivated for a couple of years), it becomes easier to manage the weeds. Ignore them for a year, and look out: they come right back. What is it that causes weeds to behave like this? Many times, a disturbance is needed to open a niche for them to exploit. In our garden, tilling is just such a disturbance. In natural settings, a drought, fire, or flood may provide the needed catalyst. In any case, once weeds are established, they are difficult to control. The dictionary definition of a weed is "any undesired, uncultivated plant." To most people, this would include half our Arizona natives. Weed scientists define a weed as "a plant that is competitive, persistent, and pernicious. It interferes with human activities and, as a result, is undesirable." This definition, though wreaking of academic pomposity, is much closer to the mark. These pests muscle their way into our space and restrict our freedom to sit in the shade and enjoy icy cold beverages. Remember the last time you were walking along barefoot and found yourself standing in the middle of a puncture vine patch? In all seriousness, weeds are the most widespread pest facing agriculture and natural resource areas. If the weed is an annual, then hand pulling or hoeing can usually effectively control it if it is done before it produces seed. Perennial weeds present greater challenges. Herbicides can be used and are effective in controlling most weeds, especially if herbicide applications are properly timed and correctly applied. A growing area of concern in wildland areas are noxious weeds. These pests are defined as "a weed specified by law or regulation to be particularly undesirable, destructive, and difficult to control." Noxious weeds are introduced to new areas by vehicles, domestic animals, water, wind, and humans unwittingly either transport the seeds on their clothing or collect the plants because they like their appearance. Once established on a new sight, noxious weeds can spread relatively slowly until the population explodes. In Arizona, noxious weeds are divided into three classes. Regulated noxious weeds are those that are well established and generally distributed in the state. These include field bindweed, puncture vine, and burclover as well as others. Restricted noxious weeds occur in Arizona in isolated infestations or very low populations. Some of these are yellow starthistle, sweet resinbush, and scotch thistle. These three occur in the Verde Valley. Prohibited noxious weeds are those not known to occur in Arizona. This list has been developed because they are found in other parts of the west and would likely be successful once they became established. Some difficulties can be encountered when trying to control noxious weeds. First, diverse land ownership can permit control on one side of the property boundary, but not always on the other. Second, people need to know how to recognize a noxious weed with some degree of certainty. Third, agencies and other partners must develop a noxious weed plan and agree on measures to be taken. Finally, resource people must be identified that can verify reports of noxious weeds. Currently, the US Forest Service, Arizona Department of Transportation, the Bureau of Land Management, Arizona Department of Agriculture, Arizona State Land Department, National Park Service, Nature Conservancy, Northern Arizona University, and University of Arizona have noxious weed interests and/or programs. In addition, last November, the Arizona Vegetation Management Association was formed to focus attention and energy on the noxious weed issue. By the way, Scotch thistle and yellow starthistle are in the Camp Verde Area and sweet resinbush is in Cottonwood. For more information or assistance in identifying noxious weeds or if you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 or E-mail us at mgardener@kachina.net and be sure to include your address and phone number. |