Bindweed (Convolvulus arvensis) is one of those plants that you really don't want taking over your garden. It is a nondescript greenish tangled mass that has been known to take over entire fields; dotted here and there are funnel-shaped flowers about 1 inch in length. These flowers vary in colour from lavender to pink. Bindweed goes by a host of other names; it is often confused with the morning glory plant. This plant can grow anywhere where there is even a trace of water; it has been found in elevations up to 10,000 feet. Its rough brownish seeds share the plant's extreme durability and can live for up to 50 years
Bindweed is exceptionally difficult to kill. Weeding will do little good; bindweed roots are long, fleshy, and fragile. If you pull too hard, you will break the bindweed root, accomplishing little. Bindweed roots can extend as long as 30 feet below the surface, with older plants having as many as 197 individual roots. The plant produces a new crop of flowers every day that it is in season - that is, June through October. Weeding bindweed by hand is like whack-a-mole; the taproot can be four feet from where the flower bud pokes up.
Another noder put it best when he said:
Somewhere under the soil, a taproot is laughing at your efforts
Fortunately, there is an effective solution to this menace. Glyphosate will stop bindweed dead in its tracks, because it kills the root. Repeated spraying is almost always necessary, because bindweed will simply not die without a fight, although repeated spraying is recommended for the sadistic feeling. If drought conditions are present, don't bother spraying - in that condition, the plant is expending all its energy simply on living. Glyphosate does not discriminate in which plants are killed, so make sure to use a cut milk jug to shield other flowers from the poison.
source: deseretnews.com, june 30th, 2002 edition