You are not the first gardener to be tricked into tolerating bindweed (Convolvulus arvensis) by its handsome arrowhead-shape leaves and trumpet-shape blooms. In the 1920s, it became one of California's most persistent weeds after gardeners grew it as an ornamental. Bindweed has been the bane of Midwest gardeners since the 1800s, when it hitched a ride into the region with some wheat seed.
As you have noticed, bindweed uses spreading roots to expand its territory. Some roots can grow to 30 feet long. Many of the kinks and elbows of bindweed roots have ready-to-grow buds. Even a small piece of root left in the ground can sprout into a new plant.
To get rid of bindweed, allow the plants to grow about 6 inches high, then cut them down. Repeat through the entire growing season. This procedure forces the plants to exhaust the food reserves they hold in their roots. Late in summer, treat surviving bindweed with an herbicide. The battle will not be over, however. Bindweed also grows from seeds, which can remain viable for 50 years. Consistent weeding and the generous use of mulches are the only ways to achieve good long-term control. It will help immensely if your neighbor joins in the control effort too.
