In some movies involving getaway vehicles and car chases, the one fleeing from the scene of the crime sometimes employs this trick: They throw spikes behind their vehicle and the spikes cause the pursuing vehicle’s tires to blow up.
Unfortunately, nature has provided us something of an equivalent to these spikes: Lawn stickers. Every year, many people fall victim to lawn stickers’ spiky seeds, which are sharp enough to puncture bicycle tires. They can also cause injury and even infection to unwitting people and animals who step on them. The best way to prevent this from happening is to remove lawn stickers from your lawn or garden altogether.
What are Lawn Stickers?
Lawn stickers, also known as Tribulus terrestris, puncture vine, goathead, caltrop (which means “spiky weapon”) and yellow vine, is a flowering plant on the family Zygophyllacaea. They like warm temperate and grow in tropical regions in Europe, southern Asia, Africa and northern Australia. They are considered weeds.
Lawn stickers are a perennial plant, growing annually during summer in cold climates. They are leafy plants with a single main root called a taproot where other roots sprout out. They grow from 10 cm to over 1 m and sprout five-petaled lemon yellow flowers. A week after the flower blooms, it is followed by a fruit that falls apart into four seeds. The seeds are hard and “horned”, spiny and strong enough to puncture rubber tires, bare flesh, plastic and other similar material. This is both a protective measure against the seeds getting eaten by animals and way for the seeds to transport themselves in other areas to grow. They typically like growing in dry, sandy soil but may withstand other types as well.
Get Off My Lawn, Stickers!
Here are some methods for you to remove lawn stickers from your lawn or garden. It has been observed that there are no quick methods to remove lawn stickers completely from your garden and they may last three to seven years before being eradicated. However, unlike most weeds, they may be easier to handle since they depend on seeds to multiply and ensure the next generation.
Get to the source. Use a hoe to cut the lawn stickers from their taproot. You may need to do this continuously in order to starve out the root. This will also prevent them from flowering and developing seeds, which is how they multiply. Using mowers for this purpose will not be effective because lawn stickers grow closely to the ground.
Pull it. Don a pair of rubber gloves and manually pull lawn stickers out. Locate the center from where the vines originate from and pull out in one swift, strong movement. Pulling lawn stickers is the best during mornings, when the soil is still moist and soft, which will make pulling easier. Put them in a plastic bag. Be sure to pick up any seeds that have fallen off while you were pulling and put them in plastic bags as well. Check under your shoes or tires for any seeds that may have gone overlooked. (Tips on how to pull weeds)
You can also use an old terrycloth and drag it along the ground for the lawn sticker seeds to cling on after. Throw the terry cloth away or burn it afterwards.
Introduce some competition. Like many weeds, lawn stickers love areas where they have little to no competition for sunlight and nutrients. Lawn stickers in particular are very sensitive to competition. Till the soil and plant in desirable plants and grass seeds. Consult your nearest plant nursery for the best plants to compete against lawn stickers, although other perennials are often your best bet.
Burning up. You can also use a propane weeder to selectively burn lawn stickers in your area. Some states are strict on burning as a form of control, so be sure to check with your locality’s regulations and ordinances before doing this step. If you want to resort to a large-scale burning operation, better hire a burn crew for this purpose.
Health is wealth. Weeds typically love growing in poor, unhealthy soil. After pulling out your lawn stickers, apply fertilizer to the soil to make it healthier. Some sources say that putting sugar in unhealthy patches of soil and watering it in will also make soil more fertile and unfriendlier to weeds.
Herbicides. You can use pre-emergent herbicides such as products containing oryzalin, benefin and trifluralin, all effective on lawn stickers. They will kill seedlings as they germinate, but will not kill mature plants. For full potency, they must be applied before the lawn stickers germinate, usually around late winter to mid-spring. Read labels and instructions carefully before using.
You can also use post-emergent herbicides after the seedlings have emerged from the soil such as 2,4-D, glyphosate and dicamba. These herbicides are more potent when they are applied while the plants are still relatively young. Post-emergent herbicides typically cause harm to other plants, so be sure to check the labels first and ask your suppliers if you are unsure.
You can also opt to employ professionals to apply herbicides in your garden if you are feeling unsure with applying it yourself.
Insect-icide. The weevils Microlarinus lareynii (seed weevil) and M. lypriformis (stem weevil) are biocontrol agents against lawn stickers. The seed weevil lays eggs in the young burr or flower of lawn stickers. When the eggs hatch, they will feed on the undeveloped seeds, preventing them from maturing and dispersing. Stem weevils do the same, only they lay their pupae on the lawn sticker’s stems, roots and leaves.These weevils can be purchased from biological suppliers.
Using insects as a form of biocontrol does not ensure that the lawn stickers will be eradicated completely. It may take time before insects establish themselves and may die if bought from another area. These weevils are also most effective when used together and when the lawn stickers are facing competition with other plants.
Concrete. Lawn stickers love growing in distressed areas, gravel paths and cracked sidewalks. You always have the option of putting concrete over the area to prevent them from growing, especially if this is an area that people regularly pass through. (Learn how to pour a concrete slab)
Here are some tips to prevent you from becoming a victim of lawn stickers:
- Lawn stickers can cause injury, so always wear footwear when walking outdoors, especially during lawn sticker season.
- Buy your bikes thorn-resistant tires to prevent lawn sticker burs from causing damage
- Sweep your lawn area regularly to get rid of lawn sticker burs, especially if you have a lawn sticker infestation.
- Clean your tires and the the underside of your shoes after going through a weed-infested path, especially during the summer.
- Don’t borrow garden tools. You may end up getting your neighbor’s weeds by transporting the seeds into your lawn!
The key to getting rid of lawn stickers is thoroughness. There’s no certainty in getting rid of them completely in one go, and you may have to do these different methods repeatedly. Also, your hard work will be all for naught if you overlook picking up the seeds afterwards (although it is best to start working before the plants even remove the seeds!) so you won’t be surprised with a new batch of lawn stickers growing next season. Blowing up tires look good in the movies, but doesn’t feel great when it happens to you! Take these measures now to prevent it from ever happening to you. If you’re interested in reading this article, you’ll surely enjoy reading how to get rid of lawn weeds.