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Before They Were Burs

Late September and Early October enjoy near-universal acclaim as the best time to be in Iowa’s woodlands. The temperatures have dropped, the bugs have abated, the leaves have begun to change, but beauty still abounds among the last of the season’s pollinators and wildlife.

Fall scenery on the Turkey River

On the right day with the sun shining, no humidity, and bumblebees merrily foraging among the goldenrod, it can feel almost too perfect. Fortunately, Iowa never lacks for natural elements to keep hikers humble.

No walk in the woods during early fall would be complete with a nice, healthy coating of burs. They seem to hide in plain sight, and even the wariest woodsman will pick up a few hitchhikers on every outing.

Plants demonstrating Epizoochory - the fancy term for dispersing seeds by attaching to animals - make up only 5% of the botanical world's diversity. But come early fall, it can feel like everything in the woods wants to make its way onto your habiliments.

Paavo Ben Slocum demonstrating the magic of Epizoochory

The sneaky plant appendages seem to emerge from thin air, but in actuality every bur you pluck out of your dog’s fur used to be a flower. Perhaps it’s worthwhile then to take a look backwards and see what the stickers look like in full mid-summer splendor, when we might just think “oh what a pretty flower!”

First and foremost, Virginia Stickseed, AKA Beggar’s Lice, AKA Hackelia virginiana. In all of the bur brigade, these tenacious little stickers might just be the fleece-wreckingest of them all.

Virginia stickseed awaiting unwary passers-by

Hackelia has caused me to throw away many a perfectly good sock, and I usually have the last of the burs exorcised from my washing machine sometime around July the following year. The plant has subtle blooms in July and August, much less showy than it’s cousins in the Borage family like Virginia Bluebells and Hoary Puccoon.

It looks so friendly in summertime!

While native, Hackelia can become quite weedy. It thrives on disturbed sites, often forming dense colonies. Extremely thick colonies can indicate deer overpopulation, as their bitter leaves tend to be avoided by our white-tailed gardeners.

Hackelia thriving in a recently-cleared area

But Hackelia has some serious competition in the “aw dangit” department. Tick trefoils – of which we have a few different varieties, all in the Desmodium genus – cover our pant legs with flat, semicircular seeds that peel off reasonably easily compared to Hackelia.

Desmodium seed pods

In midsummer, these Desmodium flowers put on a decent show, though generally only a few flowers bloom on the plant at any given time. The long bracts of delicate pink or white blossoms provide one of the few spots of color between the spring ephemerals and the late-season flowers like goldenrod or white snakeroot.

Tick trefoil in bloom

While our previous two burs generally cause more mental irritation than physical, a few spiny burs can actually pack a little punch when they latch on.

Sandburs occur frequently in disturbed sites, and if you have an encounter with them you will know pretty quickly. The thick, long-spined fruits prove sturdy enough to stick into bare skin, making for a painful experience on bare feet – say, while landing a canoe on a sandy riverbank.


Until the spiky fruits emerge, this grass superficially resembles crabgrass and grows in many of the same areas. Small rodents may eat the burs themselves, and deer will forage the grass, but they often pay for their meal by giving the seeds a ride on their fur.

Sandbur looking suspiciously innocuous

Last but not least, Burdock, AKA Arctium minus. This non-native plant has become well established along roadsides, forest edges, and other disturbed areas. The massive, fleshy leaves make it easy enough to identify any time of year, but the flowers have a distinctive appearance as well.

Bee feasting on a "weed"

The scourge of many gardeners, Burdock flowers actually do seem to attract pollinators reasonably well. The showy pink blossoms provide an excellent nectar source right up until the first frost, but quickly give way to a large and meaty bur that will hitch a ride on any passers-by throughout the fall and winter.

And my shoes aren't even furry

The burs have enough of a prickle to stick to hands that try to remove them, occasionally stiff enough to cause pain. However, the strategy appears to be quite effective since this old-world plant now enjoys a distribution throughout the Americas.

We may curse the Burdock when it sticks to our shoes, but every parent of young children has Burdock to thank for the Velcro that keeps mittens attached to coats and speeds up the “get your shoes on” hour before kids learn to work shoelaces.

In 1941, a Swiss engineer named George de Mestral noticed the tenacity of the burs and decided to investigate. Looking at the burs under a microscope he found tiny hooks that looped through the fibers in his clothing. Imitating that simple setup gave us the Velcro we have today.

Burdock (left) and Velcro (right) under a microscope

In that way, burs speak to the amazing feats of engineering plants deploy to gain an advantage over their competitors. While some seeds catch a ride on the wind or in the stomach of a hungry animal, burs have found a way to cover incredible distances – thanks in no small part to our help.

You may notice most of these burs come from plants that love disturbed areas. Turns out, humans do too. More often than not, we’re actually the ones creating the disturbance. So it stands to reason that the plants who can hitch a ride on our clothing - which we wear into a car that we drive dozens of miles to a new destination – would become phenomenally successful in our altered environment.

Looking Back

The last of the Monarchs can still be seen flitting about. The Monarchs we’ve seen over the last month will likely have either left for Mexico already, or will do so shortly. We had an astounding 55 people come out to celebrate their migration at the annual Monarch Release Party on September 4th. Public awareness is so crucial to the recovery of any species, so it’s heartening to see such an impressive crowd (in a safe setting) take an active role in helping their populations expand.

A group of 5th and 6th grade students ventured down to Motor Mill for an outdoor field trip on Friday, September 25th. The group got to see a live beekeeping demonstration, learn about food webs, and hear how natural and human history come together at the Motor Mill historic site. They couldn’t have picked a better day to be outside!

On Saturday, September 26th, the CCCB hosted a prairie seed gathering event for National Public Lands Day. Just like the Monarch party, it was truly heartening to see people spend time on their weekends to help better our natural resources. Everyone got a little practice identifying plants that aren’t flowering, and a lot of info on how the prairie reconstruction process works.

A bucket full of future prairie

Looking Forward

On October 10th and 11th, Osborne will play host to an Open Air Market in lieu of Heritage Days. Come on out and get some fall-inspired goodies!

On October 24th, we will host the 2nd annual Pony Hollow Trail 15K. We have a few pandemic-related precautions in place for this year’s registration and start/finish processes; for more details check out the website here.


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