BINDWEED  is a plant with long string like stems that twist and grow over other plants. Three bindweeds grow in the United States. They are pests to farmers because they make harvesting of crops difficult. Their many leaves shut out the sunlight from the plants used to make food, causing them to starve to death.

The worst of the bindweeds is the European bindweed, sometimes called small-flowered morning-glory. It has white or pinkish flowers less than an inch long. Its trailing stems are as long as ten feet. Its roots go deep into the ground, sometimes more than 15 feet. It is a perennial and so comes up year after year. Its flowers measure 1.5 to 3 inches 13.8 to 7.6 centimeters) long.

Fields with a lot of bindweed must be left implanted. To kill it the farmer must cultivate the field every six days for three years with a disk harrow. Today chemicals are also used to fight this weed.

The great bindweed or hedge bindweed looks like the European bindweed but has flowers one to two and one-half inches long. It is not quite so hard to control but it is also a perennial.

Black bindweed or knot bindweed has small white flowers in spikes. It is not a perennial and so is easier to kill.