Why Do Tumbleweeds Tumble? | Deep Look


Thanks to CuriosityStream for supporting PBS Digital Studios. They’re prickly. Restless. Rambling. But if most plants are perfectly content to
stay in one place, why does the tumbleweed hit the open road? Tumbleweeds start out as tiny seedlings. They sprout in late winter. By summer the plant takes on its round shape. They grow flowers nestled between thorny leaves. Inside each flower, a fruit with a single
seed develops. This fruit is different than something delicious
like cherries. Lucky for the cherry tree, a bird will carry
the fruit away in its belly and disperse its seeds. But the tumbleweed takes matters into its
own hands. Come fall, the plant dries out and dies. The seeds are still in there. Gusts of wind easily break the dead tumbleweed
from its roots. See where it was attached? It looks kind of like bones. A special layer of cells at the base of the
plant makes this clean break possible. Then the skeleton is off, shaking loose tens
of thousands of seeds as it goes. It turns out, some living things spread their
seeds better when they’re dead. Like cowboys in a Western, tumbleweeds head
out on the open range. But these icons of the American West actually
come from the east, all the way from Ukraine. They’re a common weed in Russia too. That’s why they’re called Russian thistle. They might have hitched a ride here in the
eighteen hundreds hidden among flax seeds. Nowadays, they might amble onto the freeway
and make you swerve. Or get tangled up in your irrigation system. They could even roll into your neighborhood,
pile up and become a fire hazard. But a green lawn isn’t what the tumbleweed
is looking for. It can’t compete with plants like grass. It needs a barren place like this abandoned
onion field north of Los Angeles. With each bounce the tumbleweed sends its
seeds flying. It spreads them out so they all get plenty
of sunlight and space. The coiled-up embryo inside just needs a little
water to sprout. And soon enough, this plant will strike out
on its own. Thank you to CuriosityStream for supporting
PBS Digital Studios. CuriosityStream is a subscription streaming
service that offers documentaries and nonfiction titles from some of the world’s best filmmakers,
including exclusive originals. Want to learn more about the American West? Check out their series “Pioneering the American
Frontier.” Get unlimited access today. And for our audience, the first 60 days are
free if you sign up at CuriosityStream.com/DeepLook and use the promo code deeplook during the
sign-up process. Want to keep up with Deep Look’s journey? Sign up for our newsletter by clicking the
link below. And subscribe, so you don’t miss an episode. Tumbleweeds have an unusual way of getting
around. Here’s another one. Watch Deep Look’s episode on pulsating slime
molds. See you next time!

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Reader Comments

  1. zustin nurfitriani

    I don't why but i'm feeling a bit scared now,, i'm used to see it in cowboy movie but not as big as the one in the vid 😳😳😳 they tumble upon me,, i would runaway okay 😅

  2. Brad Miller

    In highschool I lived in a dry, dusty, windy little prairie town. Tumbleweeds were a huge problem. They would build up into these massive heaps, causing businesses and schools to close, and people to become trapped inside of buildings until they were either cleared manually, or by the wind.

  3. Renville80

    There was an email forward a while back where a large pile of them covered some railroad track and the engine lost traction trying to get through. Think they had to manually clear the track to get going again.

  4. K

    Wow, I've never seen tumbleweeds tumble before, nor even seen tumbleweeds period! I've only seen them in cartoons when I was little, maybe Roadrunner?

  5. Bananappleboy World

    1:45 And here we observe wild crazios arecoziosian, or tumblecrazes for short, on the lonely alien planet orbitting Kepler 4529BC.

  6. Chelsey Abbott

    I DIDN'T KNOW THEY WERE A WHOLE PLANT!!?? I thought tumble weeds were a mass of dead weeds all tangled up and stuck together

  7. Buttercupkat Productions

    Cowboy: It's just you and me…
    Tumbleweed passes
    Bad Guy: HEY LOOK, THE TUMBLEWEED IS SPREADING IT'S SEEDS!
    Cowboy: What?
    Bad Guy: Shows video
    Movie Director: CUT! THERE IS NO TECHNOLOGY IN COWBOY TIMES!
    Everyone in crowd: I'm gonna go watch some Deep Look.

  8. Susanneskadet sinn verdiløs eksistens

    great shots of the Mojave desert, i lived in the victorvalley for 12 years, i miss that beautiful climate

  9. Wan Muaz Hurayth Wan Muhd Hisham

    tumbleweed are the number 1 skeleton why? because that thing is a dead bush always rolling around the Russia!! but i’m not from Russia i from (malaysia)

  10. T R

    This is fantastic my first home was on a court that is called tumbleweed..After moving in there was a tumbleweed rooling around on the street.

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