A few weeks ago, when the thermometer was well over 100 degrees, I found myself, hoe in hand, trying to rid my pasture of Tribulus Terrestris of the family Zygophyllaceae, commonly known as goatheads or puncture vine.
As I filled bag after bag with these lovely green plants, it occurred to me that perhaps I should raise them as a cash crop.
First, let me provide a little background on this, our favorite ubiquitous plant. The first New Mexicans would not have found themselves enamored with goatheads, because they are not native to the Southwestern United States, or anywhere in the United States, for that matter. These delicate plants with their hairy stems and cute yellow flowers are native to Mediterranean Europe and North Africa.
Some ranchers and sheep owners, who shall forever be blessed for their contributions, managed to import puncture vine into the Midwestern United States along with their sheep and cattle. Seeds of the plant infiltrated the ballast that was used to lay track during the railroad boom of the late 19th century. Moving along with the rails, the plant eventually reached California in about 1900. From rail beds, it migrated to highway borrow pits and, hence, to everywhere else in the Southwest.
Now let’s consider why raising this ubiquitous plant as a cash crop might have some appeal. The basic crop cycle has four phases — first you plant, then you cultivate, then you harvest, then you market. Let’s consider each of these in turn.
Planting, of course, involves obtaining seeds. This should be no problem, since each puncture vine plant can produce between 200 and 5,000 seeds (some evidence suggests as many as 100,000). Collecting the seeds is also straightforward — simply ride your bicycle (or tricycle for those of us in an older age cohort) along almost any rural path in the state.
Alternatively, put on rubber-soled shoes with thick — very thick — soles and walk through a patch of the lovely green vines. In either case, the spiny burrs, called nutlets or even “fruit” by the demented botanists who spend their careers studying these sorts of things, will be right there waiting for you. Each of these nutlets breaks into five pieces, each of which contains the seeds you are after. The nutlets impressed someone as looking like the head of a goat, horns and all, hence the name.
All you have to do now is pull the nutlets out of your shoes or tires. Of course, you can’t really wear gloves because the spiny burrs are too small. Not to worry — the blood that will saturate your harvest of seeds can be thought of as a special germinating fertilizer when you plant them. And, by the way, you needn’t worry about missing a few of them in the patch you just harvested, since these fruits remain healthy and ready to germinate for up to 20 years when buried in the soil.
Once you have your seeds, simply scatter them anywhere (please avoid my pasture — I already have a bumper crop). Better yet, you can actually avoid the seed collection altogether since these plants will reseed themselves with no help from you. Goatheads prefer dry soil (or wet) and they like the sun (or the shade).
If you plant them in the sun, they exhibit what the demented botanists call prostrate habit. This is a fancy way of saying that they spread out horizontally, sending tendrils as much as 6 feet from the mother stem, dropping nutlets and seeds along the way. In shady areas, they are prone to grow more vertically, so the horticulturist is presented with a wonderful variety of horizontal or vertical patches.
Cultivation is straightforward — just get a tall, cool one and watch them grow. These plants are classified as summer annuals, but don’t despair — they will always return with the first gentle rains of spring (or the first bike tire or bare foot). And even if you miss a year or two, remember the ones that last for two decades just waiting for you to disturb the soil where they lie buried.
We’ve spoken about harvesting the seeds for future use, but what about the flowers? While the lovely five-petal blossoms are delicate, they are also tiny and well-guarded by their spiny fruited friends. I do not recommend attempting to gather a bouquet for your one-and-only. The blood will probably be something of a turn-off.
So, now we come to the real challenge — marketing. Puncture vine is classified as a noxious weed. It is toxic (to say nothing of uncomfortable) to animals. It also makes hand-harvesting of crops that may be infested with the vine much more challenging.
I can really think of only one potential beneficial use of the plant — it could be used to wreak havoc or seek revenge on a person who might have wronged you in the past (Once again, I am a good person who hasn’t harmed anyone recently, so please avoid my yard).
Should you wish to remove these lovely plants from your yard or pasture (hard to believe that someone would want to, but I guess it is possible), you have four alternatives — the manual method, the chemical method, the inflammatory method or the insectivorous method.
The manual method is the recommended approach — simply get a hoe and several large plastic bags, dig the plants out by the roots (normally they are rather shallow), place them in the bags, and send them away with the trash. I actually prefer to use a specialized hoe called a winged weeder.
This hoe features blades that are swept back at an angle somewhat between that of the Korean War F-86 Super Sabre jet and the modern, stealthy F-114 Nighthawk. The swept wings on these aircraft are designed to improve aerodynamic performance at or near the speed of sound. I find that I operate the winged weeder closer to the speed of dirt. However, the blades on the back side of the weeder wreak havoc on the stealthy goatheads.
It is probably a good idea to rake the area after hoeing to get the nutlets that may bedevil your grandchildren 20 years later. Oh, and don’t forget to treat the blisters that are an inevitable consequence of this special gardening activity (at least they were for the delicate hands of your humble author).
The chemical method is more expensive, but not nearly as exhausting. An herbicide will kill the plant, but it will do nothing for the spiny nutlets. They will remain viable and in wait for any opportunity to break open and release their seeds. If you do choose this method, please be careful about the use of herbicides and disposal of their containers. They can lead to far worse consequences than stepping on a nutlet or two (or five)!
The inflammatory method, best done with a torch and a bottle of propane, can be done alone or in concert with the first two methods. This approach will kill the plants and destroy the nutlets, and perhaps set your neighbor’s field on fire if you’re not careful. There is also a certain level of satisfaction in seeing this noxious weed shrivel and disappear into a wisp of smoke.
Finally, as it turns out, there are two natural enemies of the puncture vine — the seed feeding weevil (Microlarinus Lareynii) and the stem and crown mining weevil (Microlariuns Lypriformis). These insects, which are apparently native to India and France, eat and reproduce on members of the Zygophyllaceae family and can control the spread of the plant. However, they also feed on non-host plants (perhaps your vegetables or pasture grass), and they are not readily available at your local feed store or at Walmart.
It seems inevitable that our favorite noxious weed will go on and on and on, puncturing tires and the soles of feet until you pick up your hoe (or winged weeder) and go after them. So, as you prepare to approach this task, allow me to send you forth with a slightly modified haiku.
Ah, the goathead
Lying peaceful in the garden
Delicate yellow blossom