First, a regional tour of the most aggressive perennial weeds in the U.S. - what they look like, how they spread, and why they’re so hard to beat.
Then, we work on management using Integrated Pest Management principles, starting with prevention and exclusion, moving through cultural and mechanical controls, and knowing when chemical options are appropriate.
Finally, we close with a hard look at the homemade internet sprays that are all over social media - and why some of them could do more damage to your soil than the weeds ever would.
Let's dig in.
References:
1. Montana State University Extension – Field Bindweed (Convolvulus arvensis) MontGuide MT201903AG
https://apps.msuextension.org/montguide/guide.html?sku=MT201903AG
2. University of Nevada, Reno Extension – Managing Field Bindweed (Publication 4834)
https://extension.unr.edu/publication.aspx?PubID=4834
3. University of Minnesota Extension – Perennial Weeds Identification Guide
https://extension.umn.edu/weed-identification/perennial-weeds
4. University of Minnesota Extension – Canada Thistle Identification
https://extension.umn.edu/identify-invasive-species/canada-thistle
5. University of Maryland Extension – Canada Thistle
https://extension.umd.edu/resource/canada-thistle
6. Colorado State University Extension – Canada Thistle
https://extension.colostate.edu/resource/canada-thistle/
7. SARE (Sustainable Agriculture Research & Education) – Canada Thistle: Manage Weeds on Your Farm
https://www.sare.org/publications/manage-weeds-on-your-farm/canada-thistle/
8. NC State Extension Plant Toolbox – Sorghum halepense (Johnsongrass)
https://plants.ces.ncsu.edu/plants/sorghum-halepense/
9. University of Georgia Extension – Johnsongrass Control in Pastures, Roadsides, and Noncropland Areas
https://fieldreport.caes.uga.edu/?p=62642
10. Schantz, M.C. (2025). Johnsongrass (Sorghum halepense): a review of its invasion, management, and spread in the changing climate of the Southern Great Plains. Weed Science, 73(e31), 1–7.
https://doi.org/10.1017/wsc.2025.7
11. University of Maryland Extension – Poison Hemlock Identification and Management
https://extension.umd.edu/resource/poison-hemlock-identification-and-management
12. Montana State University Extension – Poison Hemlock MontGuide MT200013AG
https://apps.msuextension.org/montguide/guide.html?sku=MT200013AG
13. Purdue Extension – Poison Hemlock: Invasive Plant Series (FNR-437-W)
https://www.extension.purdue.edu/extmedia/fnr/fnr-437-w.pdf
14. Mississippi State University Extension – Kudzu
https://extension.msstate.edu/publications/kudzu
15. Mississippi State University Extension – Torpedograss (Panicum repens)
https://extension.msstate.edu/publications/torpedograss
16. UC IPM – Nutsedge (Yellow and Purple)
https://ipm.ucanr.edu/PMG/WEEDS/nutsedge.html
17. West Virginia University Extension – Yellow Nutsedge (Cyperus esculentus)
https://extension.wvu.edu/lawn-gardening-pests/weeds/yellow-nutsedge
18. Penn State Extension – Japanese and Giant Knotweed
https://extension.psu.edu/japanese-and-giant-knotweed
19. University of Wisconsin Extension – Perennial Knotweed Identification (Mark Renz, Extension Weed Scientist)
https://renzweedscience.cals.wisc.edu/wp-content/uploads/sites/177/2025/05/Perennial-knotweed-identification.pdf
20. Oregon State University Extension – Solve Pest Problems: Grasses & Grass-Like Pacific Northwest Weeds
https://solvepestproblems.oregonstate.edu/weeds/grass-like
21. Washington State University – Perennial Weed Control in the Pacific Northwest (PNW Pest Management Handbooks)
https://pnwhandbooks.org/weed/agronomic/corn/field-silage-seed/perennial-weed-control-quackgrass-field-bindweed-canada-thistle-johnsongrass-etc-0
22. Colorado State University Extension – Weed Management (IPM)
https://extension.colostate.edu/resource/weed-management/
...Remaining references can be found on my website in the show notes for this episode. We ran out of room to list them here!
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