The Veg Plot

Mexican marigold: natural born weed killer

Mexican Marigold Plant Bindweed

This photo shows my Mexican marigold plants hardening off in the cold frame. Also known as Tagetes minuta they will likely flower in October when they’ll be standing eye-to-eye with me at 6ft tall. Some folk say they’re not an especially attractive plant, but I don’t care what they look like because, apparently, they’re a natural weed killer.

The roots secrete some compounds called thiophenes which takes on any pathogenic nematodes that dare to share its soil and usually wins. I don’t really understand any of this science stuff, other than I’ve been told it means it’ll kill neighbouring weeds such as bindweed and couch grass. My garden has too much bindweed and is riddled with the evil couch.

I’ll be looking after these young plants with more care than anything else I’m growing this year. Thus far they’re doing just fine, so the only hard part will be deciding which area of weed infested garden to try them in.


  • Thanks for sharing! I have written about best weed killers. Can’t believe Mexican Marigold are natural-born weed killer,too!
    Just discover your blog and will visit yours regularly.
    Shari Jennings

  • Did these work? I got some last week and hoping they will get to work on the couch grass on my allotment!

    • Sadly, they didn’t work. They suffered from some horrible weather and never really got going. I’ll try again if we’re ever predicted a Mexican heat-wave.

    • Alas, it turned out that we weren’t especially skilled in growing Mexican marigolds and they were decimated by wildlife before we had a chance to properly test them

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