6 surprising ways weeds outsmart us


If you’ve ever been frustrated by a weed’s seemingly amazing ability to survive and even thrive after being knocked back, cut down, or sprayed, this discussion is for you.

You’re not imagining things — weeds really do have adaptations that make them harder to kill and allow them to spread faster and easier than desired species. Add to that herbicide resistance, and animals conspiring to help spread seeds, and you’ve got a recipe for frustration.

On Monday’s RealAg Radio episode, I spoke with David Bilyea, weed technician with the University of Guelph, Ridgetown Campus, about a recent quiz he posted to Twitter. The 15 question online quiz was intended to get people thinking about resistant weed management before attending upcoming field day, but on its own, it’s a stark reminder of the many ways that weeds can spread and survive.

As herbicide resistant biotypes develop, recognizing that weeds can show up on your property through wind, water, and animals becomes even more important. (Story continues below)

How are weeds outsmarting us?

  • Dropping seed ahead of harvest: Some, like foxtail, will shed mature seeds well ahead of harvest (and continue to mature).
  • Making viable seed even when immature: Lamb’s quarters can make viable seed even when it’s not mature, and
  • Loooonng dormancy periods: Mature seeds of lamb’s quarters can stay dormant for up to 30 years.
  • Earthworms: Long thought to be a friend of the soil, earthworms are also a friend of giant ragweed, apparently, as these soil tunnel-makers have been filmed dragging ragweed seeds down as far as 10 cm into their burrows. Bilyea says that while no one is really sure what purpose the seed serves the earthworm, the ventilated, nutrient rich burrows make for a dandy survival spot for the possibly-herbicide-resistant seeds within the weed seed bank.
  • Birds, specifically water fowl, are also on the hook, as it’s not out of the real of possibility that migrating waterfowl could be picking up palmer amaranth seed in the states bordering Ontario and moving the seeds north.
  • Movement via water, wind, and fur: Some plants have adapted floating seeds, light seeds carried by wind, and prickly seeds to hitch a ride on animal fur. Weeds really are amazing, but all the ways in which they can spread really speaks to the need for a fully integrated weed management plan, says Bilyea.

Think you can beat my score  of 11/15? With the tips above, I sure hope you can! Check out the quiz, here.

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