I have always been very interested in plants, but in recent years my interest has dramatically increased. I like to see a lot of diversity in pastures, and over the years I have tried to identify as many of the plants in our pastures as I can. Of course we have the old cool-season standbys including tall fescue, orchardgrass, Kentucky bluegrass, and red and white clover. Other really important components of our pastures include warm season perennials like dallisgrass and bermudagrass, and annual crabgrass.
Along with all of those are another 30 or so species that occur at lower frequencies, but never the less probably make important contributions through their major nutrients, which are often quite high, and also through secondary plant compounds. Whether each of these these diverse non-planted species is beneficial or not is up for discussion, but amongst them there are three that I am pretty sure are not a good thing; Carolina horsenettle, nimblewill and poison hemlock. These three plants fit the definition of weeds in my book; when they are in pastures at significant levels they cause big problems. If you are in the tall fescue belt it would benefit you to learn to identify and manage these plants.
Carolina horsenettle (Solanum carolinese) is very common all across the fescue belt. It is in the nightshade family, and its fruit is very characteristic, looking like a small yellow tomato. It has spines and may be toxic if eaten at a high enough level, but that usually is not a problem. Horsenettle is one of the plants that seems to thrive in a well-managed grazing system. It is more of a problem in compacted soils, but it is also common in more healthy soils. A horsenettle stand is connected by a broad system of lateral roots that make the plant difficult to control. It has a lot of energy storage in that complex root system, allowing to quickly recover and send up new shoots. It can grow pretty low to the ground, so it is hard to completely control it with mowing. However, it does help to mow it before seeds mature so there is less reseeding. Horsenettle reduces grass productivity and when they are big they interfere with grazing. One of the worst things about horsenettle for me is when it is in hay, as the very tiny spines float in the air and get on your skin and in your eyes.
When we have a field get too much horsenettle (which is very rare) we will use an herbicide with aminopyralid (Graze on Next or Duracor), which is very good on it. These herbicides also kill clover and many other non-grass plants, but in my experience these other species recover quickly while the horsenettle stays out for many years after successful treatment.
Nimblewill (Muhlenbergia schreberi) is a native warm-season perennial grass that can invade pastures in the fescue belt. The plant looks very similar to bermudagrass, but it’s stems are finer and leaves slightly shorter and broader. Bermudagrass and nimblewill can be easily distinguished from each other; bermudagrass has a hairy ligule at the collar region of the leaf, while nimblewill has a membranous ligule. The problem with nimblewill is that it is very unpalatable. Given opportunity to select, livestock will almost never eat nimblewill. Nimblewill is opportunistic when there is bare ground in pastures. It is usually found in the shade at the edges of pasture, but if there is a lot of sod damage in winter it can quickly move out into pastures as it is a heavy seed producer. It is not clear why livestock don’t like to eat it, but it is common to see overgrazed pastures in fall that have clumps of ungrazed nimblewill scattered throughout.
If you have nimblewill present on your farm (very likely) you need to be careful about damaging the perennial sod. There are no herbicides labeled to help with nimblewill other than glyphosate, so there are no chemical options short of completely killing the sod and reestablishing a new pasture.
I said that livestock almost never eat nimblewill, but I do have a friend in Surry County, NC, Mike Jones, who taught his cows to eat nimblewill. Mike’s cows get a whole lot of diversity in their diet, and after being pinned down on pure nimblewill stands a few times, they began to eat it. Once they ate it more readily, it became less of a problem for him. My cows also have started to eat some nimblewill, especially if it is mixed with tall fescue or other palatable species, so maybe there is hope. If you have a bermudagrass-like plant that cows really don’t want to eat look at it carefully; it might be nimblewill.
Poison Hemlock (Conium moculatum) is a very poisonous plant that can cause serious problems with livestock. It is usually not eaten, but in some cases livestock take to it and eat too much. It is a biennial in that it forms a rosette with a deep taproot in the first year and then blooms in the second year. It looks like, and is related to, wild carrot.
Poison hemlock is a relative new comer on our farm. I first spotted a patch down near Stillhouse Creek about 5 years ago, and it was in the fall when it had gone to seed. I don’t know where it came from, but there were about 20 large plants. I pulled these, but as expected there were a lot of small seedlings in the same area the next year. This time I sprayed them in spring with weedmaster, which seemed to mostly kill them. However, the next year when I went to look at this place, some of those plants had recovered enough to bloom out, although there were far fewer blooms that the previous year. This time I sprayed the area twice with Graze on Next, and that did a good job on it.
Upon inspecting the area this past spring I was happy to find no poison hemlock. Unfortunately, about a week later I found a whole lot of plants under some cedar trees in the pasture right on the other side of the creek from this spot. I was getting ready to graze that area, so I hand pulled all the plants I could find, which turned out to be several hundred. This year I am going to go back to that same area on both sides of the creek and scout and spray any plants I see. This is one plant you should pay some attention to, and don’t let it get started on your farm.
As you walk your pastures, think about the species that are there and whether you can identify them. If you don’t know how to identify them, you will be at a loss on how to control them. There are many plant guides out there, and we have a description of many of the pastureland plants you need to know at the Amazing Grazing website: https://cefs.ncsu.edu/extension-and-outreach/amazing-grazing/pasturland-plants/
~ Matt Poore, NC State and Chair of the Alliance for Grassland Renewal
The Alliance for Grassland Renewal is a national organization focused on enhancing the appropriate adoption of novel endophyte tall fescue technology through education, incentives, self-regulation and promotion. For more resources or to learn more about the Alliance for Grassland Renewal, go to www.grasslandrenewal.org