Have you ever stepped on a caltrop-like spike while working in your garden? Or your bike got punctured? How about the excruciating pain that followed after the latter? You’ve definitely encountered a goat head weed if you answered yes to any of these questions.
Because I’ve had the experience and it’s not something I’d wish on my worst enemy. Lucky for you if you haven’t.
Botanically known as Tribulus terrestris or commonly as puncturevine, the goat head weed is a summer annual native to Southern Europe and can grow under a wide range of conditions. You’ll often find it growing in hot and dry areas such as roadsides, turf, driveways, gardens, pastures, and orchards.
In today’s post, you’re going to learn how to correctly identify this spikey weed, its impact including toxicity to humans, livestock, pets, and seven effective ways to get rid of it once and for all. If this sounds like something you’d want to learn then keep reading.
How to Identify the Goat Head Weed
The first thing you need to do is to properly identify the weed. Besides, you also have to determine the stage of growth because this will determine the appropriate control measure. For instance, young goat head seedlings are more suited for hand control or hoeing while manual sweeping or raking is appropriate for seeds removal.
So, if identification of the weed is that essential, how do you go about it?
For starters, look at the growing behavior. Goathead is a broadleaf vining weed that can germinate in any season. It generally grows low to the ground forming dense mats 2 to 8 feet in diameter. The prostrate stems radiate from a taproot and bear pairs of opposite leaves.
The leaflets are quite small and closely resemble mesquite leaves. Its stems originate from a central point at the taproot and unlike other vines, the plant doesn’t root from the stems. The trailing stems grow up to 6 feet long when the weather is favorable.
Besides, you also need to look at the flowers, fruit formation otherwise known as burrs, and the seeds. In this case, the goat head weed forms yellow flowers which grow up .5-inch-wide with 5 petals. After pollination, a seedpod form that is a cluster of five flat spiny burrs containing up to five seeds.
The seedpod is a flattened fruit that looks like a goat head with horns.
As the seedpod matures, it turns gray or tan, hardens, and breaks apart so that the individual spikes, or burrs, can stick into passing animals and tires. These burrs disperse by adhering to tires, shoes, and clothing of people, and the feet of animals – quite a survivor this weed is.
Each plant of this notorious weed can produce as much as 300 to 5,300 seeds in a single season. But here’s the worst part, those seeds can remain viable for more than 18 years. I say worst because it’s a nightmare for gardeners to control once fully established in an area.
To summarize, you need to check the following:
- Growing behavior (low growing)
- Leaves (small opposite leaves that resemble those of mesquite)
- Stems (grows prostate from a taproot and don’t form roots at the nodes)
- Flowers (yellow, .5 inch wide)
- Fruit/Burr (hard spikes that resemble a goat head)
- Seeds (thousands of them in a season)
Toxicity to Humans, Animals, and Pets
While a majority of the plants are beneficial in one or the other, for some the drawbacks outweigh the good. Especially, where humans, other plants, animals, and pets cohabit. When it comes to goat head weed, all parts of the plant are toxic at all growth stages.
If livestock and pets ingest the goat head leaves or young seedlings, their digestive tract will be injured as a result of nitrate poisoning. This plant can be particularly toxic to sheep, causing sensitivity to light, skin lesions, and swelling of ears and lips. Severe effects include blindness, skin necrosis, and death in young animals.
Furthermore, the hard caltrop-like seedpod or burr can puncture and injure pets, people, and livestock.
How to Control Goat Head Weed (7 Effective Ways)
1. Prevention by using mulch (where possible)
One of the most effective ways of controlling any pest in homes and gardens is prevention. This means avoiding the problem in the first place. And it applies to getting rid of weeds. In this case, you can start by manipulating the environment in which the weed thrives.
For instance, when you thickly mulch the prone area, you block the light to the ground which can be effective at reducing the weed populations. Another way could be depriving the plant of moisture which is essential for germination to take place.
2. Pull the weed by hands or hoeing
If the plants are still young with small populations, the best course of action is to uproot the weeds by hand or hoeing. To manually pull the weeds, water the affected area to soften the soil before pulling out the weeds.
If the plants have already started forming the prickly fruits but are not yet dry, wear gardening gloves to protect your hands.
Alternatively, you can remove the weeds by hoeing. This works well because each plant has a single taproot that can be severed. You just need to fold the sprawling stems of the plant back on the center of the plant, cut the taproot with a shovel or hoe and remove the entire plant.
The reason why this method only works for younger weed plants is that once they mature, any disturbance will just aid in their dispersal.
3. Manually sweep the affected area for seeds
Goat head weed’s survival lies in its ability to produce thousands of seeds that can remain viable for so many years. Therefore, the best way to get rid of the weed is to eliminate the seeds. In fact, physical removal of the seeds and plants is approximately 90% effective for control.
Once the plant goes to seed use a broom to sweep the seeds, collect and safely discard them. You can also use a rag to collect the seeds or a wet to dry vacuum cleaner.
4. Introduce aggressive competition
It is a natural law that the stronger ones survive. Apply this principle to your garden in a way to create natural competition between your plants and weeds. Make sure you plant that consumes resources like water, sunlight, and nutrients faster than the goat head weeds.
For example, you could plant competing perennial vegetation that will eventually occupy the site once puncturevine has been exterminated. Native, sod-forming, warm-season grasses such as tobosa, buffalo grass, blue and black grama are excellent choices for this purpose.
This principle follows that the healthier and richer your garden is; the fewer goat weeds you will have to worry about.
5. Make use of natural enemies (biological control)
This is an interesting one but not available for everyone.
Let me explain:
You can use natural enemies or biological control if the said latter can survive in your region. To control goat heads biologically, you can use two organisms which have proven to be effective. These are a seed-feeding weevil (Microlarinus lareynii) and a stem and crown mining weevil (Microlarinus lypriformis).
You can purchase these beneficial weevils for use in areas such as Nevada, California, and Arizona where they’re performing well. If in doubt, you can always ask for more information from your nearest extension office.
Besides, it can only work if the goat heads populations are large enough to sustain the weevils. You should not use this method of weed control exclusively because biocontrol agents do not usually eliminate their food sources entirely.
6. Burning the goat head weed
You can use propane burners to reduce the number of viable goat head seeds left on the soil surface. I recommend the Weed dragon garden torch kit which you can aim precisely and get optimum coverage exactly where you need it.
Simply run the hot flame over the puncturevine weeds and they will wither shortly after and die. The method is effective because it essentially dries up the internal moisture of the plants. Even goatheads can’t do without moisture.
Most people prefer this method because it is neither difficult nor expensive. But it’s not a good idea to set the wanted greenery or dry plant material on fire, as this can be very dangerous. To be on the safe side, discuss this method with your local fire department before purchasing a propane burner.
7. Spray with herbicides (as the last alternative)
If you only have a handful of goat weeds in your garden, it’s not necessary to use herbicides. Instead, combine some of the tactics we’ve already discussed. However, if the weeds have become a menace or their population is too high, spraying may be warranted but only as the last resort.
You can use several broadleaved or selective herbicides to easily control the plant. Spraying with a selective herbicide such as 2,4-D for instance will kill the weeds but not harm the grass. Other non-selective alternatives include glyphosate and dicamba.
Besides, you can apply pre-emergent herbicides containing oryzalin or trifluralin to kill seedlings as they germinate. Here’s a list of the best weed killers to choose from. And, always remember to read the product label before buying and spraying.
You’ve just learned how you can properly identify the goat head weed, its impact including toxicity to humans, livestock, pets, and seven effective tactics you can use to get rid of the notorious weed once and for all.
If you’ve found this article insightful or helpful, I’d appreciate it if you could share it with your connections. All the same, thanks for reading and all the best.