A friend recently asked for some quick way to rid her yard of goat heads otherwise
known as puncture vine (Tribulus terrestis). I cannot blame this friend for wanting a quick solution because this weed with its sharp seeds can make walking barefoot in any garden a miserable experience. Putting shoes on before going outdoors may protect your feet while in the garden. If you do not take those same shoes off before coming inside you could find walking indoors with bare feet also a painful experience. Alas, I cannot offer this friend a quick lasting fix because unless you get rid of the seed bank in the soil, anything you do is only short term. Instead, I have a solution that if consistently applied over several seasons will give you long term relief from goat heads.
Controlling this weed requires a three-pronged approach. You must deplete the seed bank in the soil and you must diligently remove all puncture vines as they appear before
they set seed. As you get an area cleared of this noxious weed, desirable plants or landscape structures need to be placed because bare ground is just an invitation for any weed to sprout where you do not want it.
The painful nature of the seed produced by puncture vine also makes it an easier weed to control by depleting the seed bank in the soil. To deplete the soil in your yard of puncture vine seeds put containers at all the doors to you house and a stable stool next to the contain so people can take their shoes off and pull out all the goat heads. You can also speed up the process by putting on your shoes and walking all over your garden. Take regular breaks to take your shoes off and pick out all the seeds on your soles. Do this all year regardless of the season because these seeds are present all year. If you are persistent in removing seeds from your yard, it will only take a couple of seasons.
The other part of getting rid of this weed is to hoe out every small puncture vine you see before it can produce seed. This should start as early as the weather warms up enough to work in the garden since seeds start sprouting in late spring. Once flowers
appear, seed will soon follow and then you have more seeds you will have to collect in your missions to remove the seeds.
Spraying with herbicides, organic or chemical, will not offer any long term solution for getting rid of puncture vine because they do not kill the seeds which remain viable for many years. There are puncture vine seed eating weevils imported from Europe and Asia but they expensive and will not overwinter in climates with cold winters. Herbicide or weevils alone will not control puncture vine. Combining the release of seed eating weevils with properly timed herbicide applications may work just like the solution I propose. You will still have to apply the chemicals and weevils over several growing season and this could be expensive. Additionally chemicals for the breakdown of the herbicide will remain in the environment.
To achieve long-term control of puncture vine, do not leave bare ground in your yard.
Avoid reintroducing puncture vine by not parking your car in puncture vine infested lots. Also, do not walk across vacant lots infested with puncture vine.