Bindweed (Convolvulus arvensis) is a perennial viney weed that spreads from an extensive rootstock as well as from seed. Stems may be several feet long and trail along the ground or climb on upright plants such as shrubs. Trumpet-shaped white to purplish white flowers close each afternoon and reopen the following day. It is a Eurasian native that has thoroughly naturalized itself in North America and was first documented in California in 1884 when collected in San Diego. It probably arrived in the US as a seed contaminant, but may have also been planted as an ornamental. Other names for bindweed are perennial morning glory, creeping jenny, bellbine, sheep-bine, and corn-bind.
Mature field bindweed looks very similar to the annual morning glory, with arrow-shaped leaves between 1/2- to 2-inches long growing alternately on a viney stem and trumpet shaped flowers ranging from white to pink. In contrast to field bindweed, the ornamental annual morning glory has a larger, more showy flower that may be white to blue or purple in color, a thicker stem that is sometimes hairy, and heart-shaped leaves. The twisted stems of bindweed may grow to 6-feet, forming dense mats when there are no other plants or structures upon which to climb. With warm, moist conditions, bindweed leaves are larger and vines more robust than under drought conditions.
Bindweed is a hardy plant found that typically grows below 5,000 feet elevation, reproduces both from seed and creeping roots and survives in extremely diverse environmental conditions. Seeds can remain viable in soil for 50 years or more and the plant itself is very drought tolerant. Field bindweed dies back each year, but with a deep, extensive root system and fragments as short as 2-inches forming new plants, bindweed easily overwinters without foliage.
Field bindweed, once established, is almost impossible to control with herbicides and precludes planting of certain production crops such as onions, melons, and tomatoes. Black polyethylene mulch can be an effective control if no light is allowed to reach the soil and the plant, but any holes will allow plant growth and it may take more than three years before the bindweed is killed. Additionally, once the plastic is removed, new plants may germinate from seed.