Weeds have plenty of biological tricks to spread seeds on their own, but they also get an assist from a few surprising sources, such as birds, livestock and waterways.
GROW’s webpage on Weed Seed Prevention lays out these odd but effective modes of weed seed transportation.
Beware Bird Poop
If you’ve ever stepped in duck or goose poop, you could be a weed-seed spreading culprit yourself!
In one 2017 study from the University of Missouri, scientists found weed seeds in the droppings of hundreds of duck and geese over the course of two years. It turns out these waterfowl were trafficking sizeable amounts of viable seeds – the scientists sprouted over 35,000 plants from the recovered seeds. They included notoriously troublesome weeds, including lambsquarters, Palmer amaranth, Italian ryegrass, waterhemp, common ragweed, morningglory, barnyardgrass, foxtail, shattercane, and Pennsylvania smartweed.
And some of those weed seeds could really see the world. The scientists concluded the ones with the toughest seed coats – Palmer amaranth, waterhemp and lambsquarter – could survive long enough to travel up to 1,800 miles once they’d “boarded” their birds.
See some tips on preventing your fields from becoming weed seed airports from GROW here.
Watch Those Manure Sources
We can’t blame only birds – it turns out lots of livestock can be large, mobile seed spreaders.
Manure can pack in a lot more than fertilizer nutrients – studies dating back to the early 1900s have documented weed seeds surviving in cattle, hog, horse and chicken manure.
There are ways to protect your fields from weedy fertilizer, as the GROW prevention page discusses, including using ensiled or composted manure, using heat and moisture to your advantage and running germination tests.
And of course – what goes into a cow must come out, so watch your feed rations for weed contamination, too!
Don’t Forget the Surfers
Some weed seeds are built for water journeys – like the seeds of the curly dock. Their papery wings help the seed float safely atop moving water to a new destination.
But many other weed seeds can take a similar journey due to their low density, including pigweeds, barnyardgrass, horseweed, foxtail and lambsquarter. Wherever water moves off a field – by irrigation or rainfall runoff, for example – these weed seeds can surf along as well.
There are some steps you can take, including screening devices and weed seed control near waterways.
Article by Emily Unglesbee, GROW