Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.
The first time that I saw bindweed, I thought it was a cute little morning glory. Then it showed its true colors, climbing and smothering the plants in my garden. Ever since then, I ruthlessly rip it out wherever I see it growing.
What is Bindweed?
Bindweed (Convolvulus arvensis) is a perennial vine that is related to morning glories. There are two varieties: Convolvulus arvensis var. arvensis (field bindweed) and Convolvulus arvensis var. linearifolius (hedge bindweed). It’s easy to tell the two apart. Field bindweed has broader leaves than hedge bindweed. Both are native to Europe and Asia. It is thought that they were introduced to North America as early as 1739, hitching a ride to the New World as seeds in a delivery of crop seeds.
Both varieties grow 3 - 10 feet in length. They sprawl across the ground looking for something to climb. Once they find a plant or fence, they climb it by twisting around it in a counter clockwise direction. Bindweed is very difficult to eradicate because it has deep roots. The deepest roots can grow 9 feet into the soil but most of the root system is located in the top 1 - 2 feet of soil. Even if you can pull up the top 2 feet of roots, anything below that will simply grow back and produce new vines.
The flowers are trumpet shaped like their morning glory cousins. They are white or pink and 1 to 2 inches across. They look so innocent, but they produce the seedpods which each contain 2 seeds. Those seeds can endure up to 20 years in the soil. In case you’ve ever wondered where the bindweed in your garden came from, that may be the answer: seed that was deposited decades ago. Remove the flowers to prevent them from producing the long lived seeds.
Are There Insects That Can be Released to Stop Bindweed?
Bindweed is considered to be an invasive species because it can easily climb and smother native plants as well as crops and ornamentals. It has no natural enemies here in North America to stop it. There are some insects and mites that prey on it, but they do not do enough damage to the vines to kill them.
Will Roundup Kill Bindweed?
Roundup will kill bindweed after multiple applications. The best time to start using Roundup is while the vines are flowering. You will need to spray several times. This is because Roundup works by being absorbed through the leaves and then transported throughout the plant and roots. Bindweed’s root system is so extensive that it takes numerous applications to get enough of the herbicide through all of the roots. If you do not kill all of the roots, the vine will simply sprout again.
The problem with using Roundup or any herbicide is that it kills all plants, not just the plant(s) that you are targeting. Use it cautiously and only as a last resort.
Use Mulch to Smother Bindweed
Most gardeners use mulch to smother bindweed in their gardens. They use a layer of black plastic, landscape fabric or even cardboard covered with organic mulch. This works in two ways. It blocks the sunlight so that the existing vines die from lack of light. It also prevents the seeds that are in the soil from germinating or if they do germinate, from growing. You will need to leave the mulch on for at least a year, preferably up to five years. You will also need to keep an eye on the area surrounding the mulch and remove any bindweed that sprouts around the edges of your mulch.
Remove Bindweed by Hand
This is my favorite method for getting rid of bindweed. I pull it up as I weed. I don’t get all of the roots, so it will grow back, but that’s okay. The secret is that if you remove the top of the plant enough times, the roots will die. The leaves of plants produce food through photosynthesis. If you remove the leaves, you are robbing the roots of food and they will eventually die.
Even better is weeding after a rain. The wet soil makes it easier to pull weeds and get more of the roots. Since most of the roots are in the top 1 – 2 feet of soil, you can remove a good portion of the roots when the soil is wet.
If you don’t want to or don’t like pulling weeds, you can use a pair of sharp scissors and cut the vines off at the soil level. You will accomplish the same thing: removing the leaves and starving the roots without the effort of pulling up the vine itself.
Whether you cut the vines or pull them out of the ground, you will need to do it multiple times before the roots die and stop growing new vines.
© 2020 Caren White