Ah! The Great Outdoors! Nothing beats a leisurely ride down an old road in the country or a bump or two up in the foothills! Of course, you’ll only be “riding” if your tires stay inflated. Otherwise, you’ll be taking a leisurely walk down an old road in the middle of the country, pushing your crippled bike. And almost anything beats that.

If you want to stay riding, run self-sealing tubes. Heavy duty tubes are not enough. Tire liners are not enough. If you don’t run a self-sealing tube, you will get a flat. When you do flat out, run your fingers all around the inside of the tire before putting it back on. Many spikes aren’t visible from the outside of the tire, and will flat it again if not removed.

Puncturevine: Tribulus terrestris L. from the Zygophyllaceae or (Caltrop family) and sometimes better known as a goathead, is a plant designed to survive. From the time the seed sprouts until it blooms and starts to form seed can vary, but usually only takes 2 – 3 weeks.

In Boise it’s not pessimistic. it’s realistic to expect it. From almost any vista around the foothills you will see a plentitude of goat heads! They seem like a few stray, ground-hugging weeds overgrowing the middle of the trail. Nothing to worry about you think! You’ve jumped stumps higher than your helmet. You’ve descended rock-strewn cliffs that would scare a mountain goat. You are not afraid of mere weeds! You will be.

Kind of pretty. Nice, dark green leaves. Good symmetry. Those “knuckles” where the shoots split off from the root are interesting. But, wait: what are those fleshy, hairy, spiky looking things at the end of some shoots?

Those are goatheads, a particularly nasty seed that grows in abundance around Idaho. Red circles show developing goatheads: that are softer and still fairly well attached to the plant. Yellow circles show the true enemy of inflatable bicycle tires: the mature goathead. A mature goathead is a solid lump of wood a quarter inch or more in diameter, with several very hard, very sharp, quarter inch spikes arrayed around it.

You can’t avoid them, and you can’t stop them from puncturing your tire. What can you do to protect yourself? The best (and only, honestly) thing you can do is run a self-sealing tube. The goathead punctures it, it reseals. You might end up with a slow leak, but at least you’ll have finished the ride.

Beyond protecting yourself and your tires, shoes, dog’s paws and whatever else can get stuck, what can we do? Digging them up is a start! From a goathead patrol with your riding buddies. You can’t just pull and toss them either. You have to pull them, bag them and then burn them.

Prevention and Control

In your own patch you can spray…. Spraying is the most efficient way of controlling this plant. Spray early and spray often. Puncturevine will continue to sprout throughout the summer. I have found that Roundup brand herbicide is one of the best herbicides to use as long as there’s no other desirable vegetation to keep. Roundup is non-selective and will kill all green vegetation. If Puncturevine is in grass or lawn a 2,4-D type herbicide will kill all broadleaf type plants and leave the grasses alive. Great care must be taken when using 2,4-D. This type of spray can easily affect desirable plants. As with any chemical spray, always read and follow the label.

Here’s a fun video from the City of Boise and Boise Bicycle Project that tells the whole story and don’t forget to hit up the Boise Bicycle Project’s Boise Goathead Fest for more fun August, 2023!

Boise Goathead Fest – http://www.boisegoatheadfest.com