“A weed is simply a plant growing out of place or growing in a site where it is not desired.” Those are the thoughts of Dr. Barron Rector, Texas AgriLife Extension Service range specialist. And he said following this year’s drought, wildfires and tons of imported hay, there may be many more weeds for landowners to deal with, and some could be invasive species or even toxic.
“The soundest way to control weeds is to prevent the invasion, which means we must understand the biology, limit the movement, understand the human behavior and actions that can cause the spread, and understand the pathways for its introduction,” he said. Some “weeds” may be a desirable plant in one location and a weed in another, Rector said. For instance, native weeds serve a role of protecting the soil surface after a disturbance, reducing raindrop impact and solar radiation, and providing some organic matter on the soil surface and below ground. These native weedy plants depend on natural disturbances, such as grazing, fires, flooding, drought, mudslides, earthquakes, volcanoes and land development to spread and reproduce. However, foreign or exotic invasive plant species can survive, reproduce and advance on the same kinds of soil disturbance and human management that produces native weed and brush problems.
“Our major problem with land management today is our inability to recognize an invasive plant species and deal with it accordingly,” Rector said. Invasive species of weeds can cause economic or environmental harm due to habitat degradation, displacement of native plants threatening the reduction of wildlife food resources, alterations to the ecosystem of a region or alterations and changes to natural waterways.
“Invasive plants are those that have a tendency to spread and invade healthy landscapes ultimately causing some kind of negative impact,” Rector said. “Invasive plants are often best defined as plants that do not stay where they are planted.”
Because of the recent drought many livestock owners have opted to buy hay from out of state rather than selling their herds. “That hay is coming from Louisiana, Tennessee, Nevada, Florida, Nebraska, Kansas and other surrounding states,” Rector said. This sets up a potential problem because interstate commerce of hay is not regulated for the most part. Many landowners and livestock producers could be setting themselves up for weeds they’ve never seen and introduce potentially invasive plants.”
According to Rector, “It’s a Catch 22.” Producers bought the emergency hay to feed and hold on to their herds, but there is the potential that an unwanted plant could be introduced that will cost more management dollars in the future trying to get rid of it.
Producers need to start now learning what plants they should be on the lookout for. If the hay was purchased from Nebraska, Kansas, Montana, Wyoming, Utah and Idaho, producers should watch for an invasive plant called leafy spurge. If they purchased hay from Florida to Louisiana, that zone is known for the invasive tropical soda apples weed. Other plants of concern include Canada thistle, spotted knapweed, blessed milk thistle, Russian knapweed and yellow star thistle. Because of their aggressiveness, these will often be the plants that come up on the disturbed areas.
Not only will these invasive weeds keep landowners from producing valuable grass resources in the future, but they can take the place of native weeds that would have come up, such as broomweed, which provides seed that feeds birds such as quail.
Rector said there are several things a landowner needs to do now to prevent problems later. The first thing to do is be aware of what invasive plants occur in the area hay was purchased from and know what those plants look like. Each state has an invasive plant website or every state can be found on the U.S. Department of Agriculture’s invasive and noxious weeds list at http://plants.usda.gov/java/noxiousDriver.
Land managers should be on the lookout for these invasive weeds beginning in March because if they are a warm-season annual they will be germinating then. In general, annual weeds are treated with herbicides when the plant is 3-6 inches tall. It is important to know what the plant looks like in the seedling, rosette and the early vegetative stages because that is when the chemicals and management practices are the cheapest. “By the time most weeds are flowering and setting seed, it is too late to use a chemical to control most annual plants,” Rector said.
Once a landowner can identify the plant, they then need to know the recommendations for management to reduce the impact or eliminate it from the land.
Landowners can go to http://essmextension.tamu.edu/plants and find a choice of plant identification links that will help a landowner not only identify a plant, but also learn about its habitat, toxicity to livestock and management strategies.
To prevent invasive plants from spreading producers should limit the areas where hay is fed and continue to monitor. With the weather forecast predicting continued drought, seeds have the ability to sit in the soil for several years before they emerge.
For more information on this subject, contact Missy at the extension office at (940) 538-5042 or 538-5052, or via email at email@example.com.