The perennial weed often called Morning Glory is actually Field Bindweed (Convolvulus arvensis), a pervasive and tenacious plant that frustrates gardeners worldwide. This invasive species is known for its trumpet-shaped flowers, resembling the ornamental annual Morning Glory, but it possesses a far more aggressive nature. Dealing with this plant requires a targeted, multi-year strategy to successfully eradicate its extensive root system.
Why Morning Glory is Difficult to Eradicate
The primary reason Field Bindweed resists simple removal is its deeply penetrating and vast perennial root system. This weed develops a white, fleshy taproot that can descend as far as 9 feet into the soil, anchoring the plant securely. Horizontal roots, or rhizomes, form an extensive underground network, with most activity occurring in the top two feet of soil.
These roots store large reserves of carbohydrates, allowing the plant to regenerate vigorously even after the above-ground foliage is removed. The roots are brittle and easily break apart when disturbed by pulling or cultivation. Disturbing the plant mechanically can be counterproductive, as a root fragment as small as two inches can sprout into a new plant. Simple hand-pulling or shallow tilling often serves to spread the infestation rather than control it.
Non-Chemical Control Methods
Controlling established Field Bindweed without chemicals requires relentless effort focused on exhausting the massive root reserves. One method involves exhaustive and careful digging, using a garden fork to loosen the soil deeply and remove as much of the root mass as possible. This labor-intensive technique must be repeated every two to three weeks, as remaining root fragments quickly regenerate shoots.
Repeated cutting or mowing is a cultural control method designed to starve the root system by preventing photosynthesis. For this to be effective, the top growth must be cut back every 10 to 14 days over the entire growing season for at least two years to fully deplete stored energy. Smothering the infestation with thick, opaque material, such as heavy black plastic or cardboard covered with mulch, also works by blocking all sunlight. This occlusion method requires the material to remain in place for one to five years for complete eradication. It must extend past the visible growth to cover the far-reaching rhizomes. Solutions like household vinegar or boiling water offer limited success, as they destroy the top growth but fail to reach the deep, carbohydrate-rich perennial roots.
Choosing and Applying Systemic Herbicides
For the most effective control, a systemic, or translocated, herbicide is necessary to reach and kill the deep root structure. Unlike contact herbicides that only burn the leaves, systemic products are absorbed by the foliage and moved throughout the plant, including down to the roots and rhizomes. Effective active ingredients include glyphosate, dicamba, and quinclorac, which must be applied when the plant is actively moving nutrients down to the roots.
The optimal time for application is late summer or early fall, often when the plant is flowering, because the plant is naturally moving sugars to its roots for winter storage. This translocation process carries the herbicide deep into the root network, maximizing the kill. To protect desirable plants nearby, a targeted method like painting the herbicide directly onto freshly cut stems or leaves is advisable rather than broad spraying. Always follow the product label instructions precisely, as a single application is rarely sufficient, requiring multiple treatments over several seasons.
Preventing Recurrence and Long-Term Management
Achieving initial control is only the first step in a multi-year management plan, as Field Bindweed seeds can remain viable in the soil for up to 50 years. Continuous monitoring of the treated area is essential to catch new sprouts and seedlings before they establish deep root systems. Any new growth should be immediately removed or treated with a spot application of herbicide to prevent the plant from replenishing root reserves.
Establishing competitive ground cover is a highly effective long-term strategy to suppress new infestations. Dense plantings of sod-forming grasses or tall, shade-producing crops can outcompete the bindweed, which struggles in low-light conditions. This approach reduces available light and space, making it difficult for new seedlings to thrive and for established plants to regain strength.