If you’ve ever had pigweed take over your garden, lawn, or farm, you know how stubborn and relentless this weed can be. It seems to pop up overnight, grow at lightning speed, and before you know it, it’s outcompeting your plants for nutrients, water, and sunlight. To make matters worse, certain types of pigweed—like Palmer amaranth and waterhemp—have developed resistance to some of the most common herbicides. So, what’s the best pigweed herbicide, and how can you get rid of this invasive plant for good? Let’s break it down.
Understanding Pigweed and Why It’s So Hard to Kill
Pigweed is not just one weed—it’s a group of fast-growing, aggressive plants in the Amaranthus family. Some of the most problematic species include Palmer amaranth, redroot pigweed, and smooth pigweed. These weeds are notorious for their ability to produce thousands of seeds in a single season, which makes long-term control challenging.
Borman (2024)
This pesky plant is a type of invasive weed that grows aggressively and competes with your beloved grass and garden plants for nutrients, light, and space.
Borman (2024) this pesky plant is a type of invasive weed that grows aggressively and competes with your beloved grass and garden plants for nutrients, light, and space.
One of the biggest problems with pigweed is herbicide resistance. Over time, pigweed has adapted to survive certain chemicals, making it more difficult to control with traditional herbicides. That’s why it’s crucial to choose the right herbicide and apply it at the right time to prevent resistance from spreading.
Pre-Emergent vs. Post-Emergent Pigweed Herbicides: What’s the Difference?
When it comes to herbicide control, you’ll find two main types: pre-emergent and post-emergent herbicides. Knowing when and how to use them can make all the difference in keeping pigweed at bay.
- Pre-emergent herbicides for pigweed: These herbicides work by preventing pigweed seeds from germinating in the first place. They’re best applied in early spring before pigweed starts to sprout. Some of the most effective pre-emergent options include Pendimethalin (Prowl H2O), S-metolachlor (Dual Magnum), and Atrazine.
- Post-emergent herbicides for pigweed: If pigweed has already sprouted, you’ll need a post-emergent herbicide to kill actively growing plants. These herbicides work best when pigweed is still young and small—typically under four inches tall. Effective options include Glyphosate (Roundup), Dicamba (Xtendimax), and 2,4-D.
The Best Herbicides for Pigweed Control in Lawns
If pigweed is taking over your lawn, choosing the right herbicide is key to stopping its spread. Here are the best options based on your needs:
1. Best Pre-Emergent Pigweed Herbicide: Dithiopyr (Dimension)
To prevent pigweed from sprouting in the first place, a pre-emergent herbicide like Dithiopyr is highly effective. Applied in early spring before pigweed seeds germinate, this product creates a barrier that stops new weeds from emerging while being safe for most established lawns.
2. Best Post-Emergent Pigweed Herbicide: 2,4-D + Dicamba
If pigweed has already invaded your lawn, a post-emergent herbicide containing 2,4-D, Dicamba is a great choice. These broadleaf herbicides target pigweed without harming most turfgrasses. They work best when applied to young pigweed plants before they mature and produce seeds.
3. Best Natural Alternative: Vinegar-Based Herbicides
For homeowners looking for a more eco-friendly solution, 20% acetic acid vinegar-based herbicides can burn pigweed on contact. However, they only kill the top growth and may require repeated applications to fully eliminate the weed. Be cautious, as high-strength vinegar can also damage surrounding grass.
How to Prevent Pigweed from Taking Over North Texas Lawns
Herbicides alone won’t permanently eliminate pigweed from your lawn. In North Texas, warm temperatures and frequent droughts create ideal conditions for pigweed to thrive. An integrated weed management approach is essential. Here’s how to keep this stubborn weed from coming back:
- Rotate Herbicides: Pigweed is notorious for developing herbicide resistance, especially in hot climates like North Texas. Switching between different pre-emergent and post-emergent herbicides can help maintain effectiveness.
- Maintain a Thick, Healthy Lawn: Dense, well-maintained turfgrass like Bermuda, St. Augustine, or Zoysia can naturally crowd out pigweed and prevent it from taking root. Regular fertilization, proper mowing, and deep watering encourage strong grass growth. Go to our Grapevine Lawn Care service page for details on how we can help.
- Use a Pre-Emergent in Early Spring: Applying a pre-emergent herbicide, such as Dithiopyr or Prodiamine, in late winter to early spring will stop pigweed seeds from sprouting before they become a problem.
- Mulch Flower Beds and Bare Spots: In garden beds or areas without grass, a thick layer of mulch (at least 2–3 inches) will block sunlight and prevent pigweed germination.
- Hand-Pull Young Pigweed Plants: If pigweed does sprout, removing it by hand before it produces seeds significantly reduces future infestations. Be sure to pull the entire root system to prevent regrowth.
Final Thoughts: Finding the Best Pigweed Herbicide for Your Needs
Choosing the best pigweed herbicide depends on when you’re applying it, what type of pigweed you’re dealing with, and whether you’re managing a small garden or a large field.
For the best results, use pre-emergent herbicides in early spring and follow up with post-emergent treatments if pigweed starts to sprout. Always rotate herbicides to prevent resistance, and combine chemical control with cultural practices like mulching and cover cropping for a long-term solution.
If you’ve been battling pigweed in your yard, what’s worked for you? Share your experience in the comments!
References
Borman, K. (2024, August 10). Tips to prevent and kill pigweed in your lawn. House Digest. https://www.housedigest.com/1633181/prevent-kill-pigweed-growing-lawn/
