Feed or Foes? Livestock can be trained to eat the nuisance plants in some cases
Areas in western South Dakota that have been impacted by wildfires may have rebuilt fences, re-homed livestock and recovered from other damages, but there’s a secondary problem that’s creeping up just about as fast as the flames blazed across the prairie.
It’s Common Mullein, and it’s becoming far more “common” on the range then landowners would like.
“We’re seeing huge areas of Common Mullein growing in Jackson, Custer and Fall River Counties , particularly out on the hills and in the burn areas where the weed has just taken over,” said Brenda Sievers, South Dakota Deparment of Agriculture (SDDA) plant industry manager and ag inspector. “When there’s a drastic change in the environment such as a a fire, that’s when weeds like Common Mullein take over.”
A biennial species, Common Mullein produces yellow rosettes in its first year of growth followed by mature stalks that produce massive amounts of seeds in the second year. Its deep root system allows it to thrive well in even the driest conditions, and Sievers said now is the time to get a handle on the weed patches before they spread from just a few plants to hundreds per acre.
“Common Mullein has a very fuzzy leaf, and because of that, there are some challenges to using herbicides to control it,” she said. “Producers should address these weeds while they are still in the rosette stage. If sparse, they can be mechanically removed, but a surfactant is the most effective.”
While weed overgrowth issues vary by county throughout the state, there are seven noxious weeds in South Dakota that seem to plague producers the most including: Leafy spurge, Canada thistle, Perennial sow thistle, Hoary cress, Russian knapweed, Purple loosestrife and Salt cedar.
“Noxious weeds are defined as being capable of reducing production of crops and livestock, are not native to the state and are perennials,” said Sievers. “By far, the Canada thistle seems to be the most problematic because it covers the most acres in the state. You can’t rely on cows to eat them unless they are short of forage or in a very lush state. Producers can consider mowing them down or using herbicide controls to keep them from spreading.”
Pat Guptill, a rancher from Quinn, S.D., says the thistles are there for a reason, and instead of fighting nature, he has trained his cattle to eat the purple-headed weeds.
“If you have something growing, and it’s green, livestock will eat it, so don’t kill it,” said Guptill, who was awarded the South Dakota Leopold Conservation Award in 2013 for his environmental stewardship practices. “If there’s available forage, let’s get the cows to eat it. Thistles are very good feed with 22-24 percent protein, and cattle will readily eat it once they start. We pour molasses on our thistles to encourage our cattle to eat them, and it works. I’ve yet to find a weed my cattle won’t eat. I believe every time you use chemicals, you’re not only killing the weeds, but the good forbs, as well.”
Guptill is anticipating a drought for summer. His normal forage availability is 3,000 pounds, but it’s currently less than 1,400 pounds
“We are limited on forage right now as we’re operating on less than four inches of rain in the last year, but we know our stocking rates, and we don’t budge from that number ever,” he said. “It’s important to know how much forage you have and how much you can take off without uncovering ground. If you leave it bare, the land takes longer to respond to moisture.”
Making sure every blade of grass counts, Guptill said weeds are nature’s way of showing a rancher where improvements need to be made in management.
“A plant was put on the ground for a reason,” said Guptill. “If you have Buffalo Burr growing across your land, that’s Mother Nature’s protective barrier for the areas your cattle have grazed bare. If you have a weed growing that cattle will not eat, it means you have messed up the land so bad that Mother Nature wants you off of it. You have created the problem, so let’s not make it worse by spraying it. Instead, let’s go back and fix the problem. The weed patch happened because of something that changed the environment 3-5 years ago. Step back and consider how a change in management could solve the problem. Perhaps that’s timing of grazing, deferred grazing to let the land rest or length of grazing.”
Guptill moves his cattle to fresh pastures weekly, and in some cases every day, to manage the land and allow for regrowth. With more forage cover, there’s less opportunity for weeds to creep in, and the cost savings on chemicals has been huge.
“We have gotten away from chemical use on the ranch and believe they should only be used oin an emergency,” he said. “I figure I’ve spent 4-5 times what my land is worth over the years on chemicals to fight Canada thistles, and I was never getting ahead. Now the only place I can’t control the thistles is where my pastures bump up to fields with runoff and drifts coming onto my land.”
Guptill also relies on bioagents like bugs to reduce the thistles in his pastures.
“We buy our bugs from Integrated Pest Management and turn them loose,” said Guptill. “It’s a great tool in our toolbox, and if you look at the thistles we do have growing, it’s easy to see how effective these bugs are at reducing the spread of these weeds. We will never eradicate thistles, but we do have control of them.
Sievers argues that herbicides are still the best method for controlling Canada thistles; however, she says bugs can be used to manage leafy spurge quite well.
“We have collection points throughout the state where we sweep for bugs, and producers can pick them up from us free of charge,” she said. “We will start collecting in mid-June, and landowners can contact us for the nearest spot where we might be sweeping. These bugs work marginally for Canada thistles because they have to be located in a very undisturbed location; however, for leafy spurge, bugs work very well. I still do recommend a perimeter spray to keep the leafy spurge from spreading any further, and remember that any bio-agent isn’t going to get rid of the problem completely. It’s going to take 3-5 years to show improvement.”
For Bruce Smith, Montana State University Extension agent in Dawson County, there’s one bio-agent that works to address the leafy spurge problem every time — sheep.
“This is the worst year I’ve ever seen for leafy spurge in this area, which tells me some of these producers may want to consider getting some sheep on their land,” said Smith. “When you go into the low spots and spray for these weeds, you’re also killing the good forbs, shrubs and trees, too. But sheep, they will go out and grae the leafy spurge; they seek that stuff out! If a guy doesn’t want to own sheep, find someone who has them and let them graze your ground.”
Smith says the leafy spurge is producing seed already this spring, and he fears the plant population could get pretty dense as the summer progresses.
“If you are going to introduce bugs, keep in mind that the bug population dies as the leafy spurge is depleted,” said Smith. “So as the bugs kill the plants, I would follow up with spray to kill the leafy spurge completely. Otherwise, with their 30-foot root system, the bugs suppress the weeds enough to think you have it handled, and once the bugs die out, the weeds come back in a hurry.”
With the dry conditions, Smith echoed Guptill’s sentiments — cattle can learn to eat weeds. However, it takes some conditioning for them to figure it out. In the meantime, he warns producers about overgrazing.
“Grass is looking pretty short out here,” he said. “Cattle are already cruising the countryside looking for every blade of grass they can get. It’s tough. Once the ground is bare, that’s when weeds start popping up. We’re seeing more Russian thistles and knapweed along the highways. The earlier we can hit those weeds, the better, and in a year like this one, noxious weeds are going to stick out like a sore thumb. Hitting them with a spot spray here or there could prevent a full-blown invasion. Save yourself some time and money by addressing the issue sooner rather then later.”
Contact your local Extension agent or county weed office for best management tips on the noxious weeds most prevalent in your area. Weed and pest control recommendations can also be found at https://sdda.sd.gov/ag-services/weed-and-pest-control/weed-pest-control/
There are many routes available to addressing weed problems, and implementing a few key practices could stamp out weed problems and allow more forages to grow.