By Darren Hefty

As fall approaches, there is excitement building for harvest, kids back in school, and a host of other things.  Don’t miss out, though, on perhaps the best opportunity of the year to wipe out weeds for good.  Perennial and biennial weeds are different.  Obviously, they live longer than one year, but what does that really mean?  For weeds like Canada thistle or leafy spurge to survive through the winter, they have to move large amounts of food down deep into their root systems.  Why not send a strong dose of a herbicide down there, as well, to kill the weeds, roots and all, for good?

There are a few keys to great fall weed control in pastures and non-crop areas.

  1. Timing – This is by far and away the most critical piece of the puzzle.  Even if you choose the best product and the ideal rate, if you spray too late you won’t get the job done.  The IDEAL TIMING IS ABOUT 2 WEEKS BEFORE THE FIRST HARD, KILLING FROST.  This gives time for translocation of the herbicide throughout the root system.  Also, I prefer the fall timing versus spring or summer for many weeds because even if you don’t completely wipe out the weed this fall, you will at the minimum severely weaken it so a harsh winter could finish the job for you.
  2. Product selection – There aren’t many products that move well in the plant and get down through an extensive root system.  In row crops, Roundup is the one product we count on.  In pastures and non-crop areas, it’s often Milestone and Tordon that play key roles.  Milestone is the best product choice for thistle control.  Tordon is the best for leafy spurge.  Products like 2,4-D and dicamba do a nice job burning off top growth but fail to adequately take out the roots, meaning tough perennial weeds often grow back.  Also, don’t ruin your good herbicide with 2,4-D or dicamba. 2,4-D or dicamba mixed with Milestone or Tordon will often shut the plant down before the systemic herbicide can kill the roots.  If you want the best kill on perennials or even biennials, don’t add 2,4-D or dicamba.
  3. Rate – You need to apply a rate strong enough to deliver a lethal dose to every growing point on the weed in order to completely take it out.

I remember the sticker shock I had when I saw that it might cost $15 per acre to take out a weed problem in a pasture of ours.  Then, I really did the math.  In over 100 acres of pasture, there were a total of 12 acres of weed patches.  $15 X 12 acres = $180.  When you divide that out over the 100 acre pasture it was an average of $1.80 per acre, so no big deal at all.  Then, you look at the university and private studies showing that for every one pound of weed growth, you lose two pounds or more of grass feed for your animals; and you can see very quickly how important weed control is.

2,4-D and dicamba are not nearly as cheap as they once were.  You may spend $7 to $10 for a decent rate.  Chances are you’ll need to spray it at least twice a year to keep weeds out of your pasture.  In the meantime, you could have saved a trip across the pasture, years of frustration, and likely a bunch of money by choosing a permanent solution for your weed control issue, like Milestone or Tordon.  Don’t get distracted by everything else that’s going on this fall.  Stop your pasture weeds once and for all.