Puncturevine is a common Westside menace. Combatting it is easier than you think.

Puncturevine has a single, smooth stem and spreads vines from there, so pulling a large plant and its root is easy – and satisfying – if you can grasp the central stem. Photo by Christine Stanley

Thorny issues abound on Salt Lake’s Westside. My favorite to combat? Puncturevine, the aptly named weed that’s more commonly called goat heads for the thorny seeds it produces.

Puncturevine (Tribulus terrestris) is a noxious and invasive plant originating from the Mediterranean area. You’ve probably encountered puncturevine on the Jordan River Trail, where the thorns stick into bicycle tires, pet paws, and shoes. My own deep dislike of these thorns stems from an incident when I was eight. On an early autumn afternoon, I watched helplessly as the neighborhood bully pushed a barefoot little boy off a fence into a patch of sharp goat head thorns.

Now that I’ve made puncturevine out to be a menace to unsuspecting children, pets, and cyclists, I have a secret to share: It’s easy to remove, but timing is important!

Starting in mid-June, check your property and public green spaces each week for the nascent vine. A single, smooth stem connects the multi-spoked web of vines. Simply grip it below the branches, pull up, and dispose of the whole plant. Remember the goat head thorns are seeds, so watch for thorns that get left behind and check shoe soles for thorns before leaving the area.

When the first frost hits, the plants die. Remaining thorns will winter over and begin sprouting in late spring. You can remove the thorns by pressing on them with a foam board, vacuuming them up (for very compacted soil), or using other tools that are available online.

The author displaying a particularly impressive specimen. By her own estimate, Christina Stanley has pulled over 1,000 pounds of puncturevine over the last three years. Photo courtesy of Christina Stanley

Whether you’re pulling the weed or collecting the thorns, removal is straightforward, but persistence and consistency are key to eradication. They need very little water, so can live almost anywhere that a single seed can find soil. They also spread via construction vehicles, so keep an eye on areas where utility work has disturbed the soil.

Landscape crews and homeowners tend to make several common mistakes that spread and prolong the problem. Chemical herbicidal sprays only slow down the first wave of germination. Most people apply it too late and the thorns have already formed. So don’t spray them.

Weed whacking, mowing, and tilling not only spread seeds around, but they can also leave much of the plant intact. These methods only help the plants disperse the thorns/seeds.

If you use any kind of landscape barrier, remember that weeds of all kinds will exploit any gaps. Once the barrier is compromised, puncturevine can sprout and spread out quite happily on top of your hard work. Wood chips or mulch should cover thorns 6-12 inches deep and be applied before germination; however, this depth isn’t usually feasible along sidewalks and in park strips, where puncturevine tends to cause the most damage.

Competition planting, or planting other vegetation to counter the puncturevine, is a nice sentiment, but tends to complicate removal. Eventually the puncturevines overcome the intentional plantings. So removal by hand is still the better solution, and should be done first.

Not everyone likes weeding. But I love it. When my children began attending school, I would pull out puncturevine along their route. It was a small thing I could do to protect the many kids walking and biking there.

A few years ago, I took up running. I began noticing puncturevine in other areas, so I would pull it and toss it in the nearest garbage bin. In 2020, a 400 square-foot park strip at a nearby convenience store was so overwhelmed by puncturevine that I hauled over my waste bin and spent six hours removing 100 pounds of the plants and thorns. The same summer, I decided to branch out.

In 2020, I removed 300 pounds of puncturevine from park strips and public natural spaces in one square mile, and again in 2021. Last year I hit 500 pounds of puncturevine, but I had to reduce my area of coverage. In national parks, canyons and in every city along the Wasatch Front, I have found puncturevine, and removed it where feasible.

If I could eradicate this thorny pest all on my own, I would. I enjoy the work. But some extra hands would be fabulously helpful. Even if you don’t want to become an urban weed warrior, you can do simple things to help: educate business owners and neighbors; stay on the trail; immediately check your shoe soles or bike tires after you go off-trail, and put any thorns in the garbage.

Do you like programming? A now-defunct public program had an online interactive map of puncturevine infestations in SLC. Could you be the person who creates a similar tool? For those of you who relish hands-on plant therapy, consider adopting a public space or organizing a volunteer project. And if you see me out there this summer in my white t-shirt, jeans and bandana, see if you can find a way to pay it forward.

If you’re more into existing programs than building your own, the Jordan River Commission is offering a $2.00/lb bounty on puncturevine pulled along the Jordan River corridor through September 2023. To learn more about how to register for eligibility in the program, visit https://jordanrivercommission.com/wanted-puncturevine/.