Weeds As Protectors: Part II

In my last article on The Weed Experiment, I wrote about testing out mechanical control of weeds using a shredder. Check with the Fayette County Record if you missed this article. They may have a copy you can buy. This article goes into more detail and again, “Your results may vary.”

While I use the word mower, the machine is actually a shredder. A mower uses a sharp blade to cut grass. A shredder uses a blade with a blunt edge to shred grass. Provided the blade is sharp, mowing cuts the grass blade evenly across. Shredding makes a ragged edge cut and pulls on roots. To properly sharpen a shredder blade, create a flat edge at its thinnest point. This helps kill weeds.

Shredding a pasture for weed control is more about the weeds than the grass. The shredded edge of the grass or weed causes the plant to lose water. When cattle shred grass leaves, they leave a small amount of saliva on the leaf that helps the leaf heal. Open wounds on weeds cause the plant to desiccate quickly. This loss of water helps the weed to die or sets back its growth. When shredded, grasses usually recover more quickly than weeds.

During my experiment on controlling weeds, the major weed species I was trying to manage were Western ragweed and dove weed. Other pasture weeds are not a serious problem as cattle tend to eat most of them, or they never outcompete the grasses to become a problem. I have other weeds that are a problem in other pastures.

Readers may be familiar with the fall droughts of the past two years. The adaptable rotational grazing plan has always left me with a winter grass stockpile. It has always helped that we have gotten some fall rain, but with little to no rain in the past two seasons, fall pasture growth was slow at best.

What surprised me was that the unmowed areas of dove weed and ragweed seemed to protect the grasses below from drought damage. It makes sense because the weeds shaded the grass and protected it from the hot, dry winds. Who would guess that weeds would come to the rescue? As far as water competition was concerned, the weeds made little difference. Areas without the weeds suffered more. In fact, one area that was unmowed and irrigated suffered the least and was still grazed more than other unmowed areas.

Irrigation did little to help normal fall forage growth. In fact, the cattle tended to graze the irrigated areas closer to the ground than I prefer. But when rain and winter grass began to grow, these areas were the first to green up with winter forage. This was both a blessing and a curse.

The areas I mowed in the summer of 2024 and 2025 were grazed much more than the control area in the same pasture. Cattle avoided grazing unmowed grass in the areas with dove weed and Western ragweed. It’s not that they didn’t graze these areas, they just didn’t graze them as much. Even after the hard freeze on March 17, the cattle ignored the unmowed areas.

Before the freeze, the Bahia grass was beginning to green up and show significant growth. The Bermuda grass was still dormant in thick growth areas and slightly emerging in mowed areas. The winter pasture grass was growing, but a lack of rainfall kept it from being as tall or thick as it was in spring 2024.

After the March freeze, everything got knocked back hard. The winter grasses had freeze damage. The Bermuda grass seemed to be dead everywhere. The Bahia grass looked dead but showed some signs of life when I snapped a few rhizomes. I thought the Bermuda grass would come back because it has stolons and rhizomes.

Before the March freeze until the “Big Rain” on April 12 (we got 2 & 3/10 inches), it had remained one of the driest fall, winter and spring’s I can remember. That includes the drought of the 1950s. Of course, I was just a kid, but I tended to pay attention to the garden and the cattle even then.

This April I began digging holes to plant trees, installing irrigation pipe and digging up bulbs. To my surprise, the Bermuda grass had large patches of dead grass. The results of digging showed that mowed areas had died almost completely. Thick Bermuda grass areas with dead grass and weeds covering the ground had more rhizomes alive than anywhere else. Again, weeds to the rescue.

Bahia grass was the winner in the return to feeding status. In unmowed areas, the grass returned quickly to give the cattle something to eat earlier than even a large number of fast growing edible weeds. While there were fewer weeds and winter grasses mixed in the Bahia, the cattle grazed more there than in mowed areas with winter grass. The cattle easily broke the dead stems of the dove weed and grazed. Dove weed was no longer an obstacle.

Conclusion: I always hear complaints about weeds, but I learned something from my weed experiment. Weeds protected the grasses against overgrazing, drought and freeze damage, and kept the soil from becoming bare. My experience these past two fall seasons taught me that having a mixed pasture of grasses and weeds is by far the best situation.

One final note. The Bionutrient Institute has shown that the most nutritious beef comes from animals that eat the greatest diversity of weeds, grasses and plants. The nutrition level has nothing to do with breed, age, tenderness, fertility or climate, but what the animal eats. Maybe ranchers should ask what weeds are best for cattle.

David E. Will is a local rancher and consultant. He can be reached by phone or text at (830) 629-9876.