University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Historical Materials from University of Nebraska-Lincoln Extension Extension 2003 Bindweed Identification and Control Options for Organic Production Laurie Hodges University of Nebraska&#8211Lincoln, [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/extensionhist Part of the Agriculture Commons, and the Curriculum and Instruction Commons Hodges, Laurie, "Bindweed Identification and Control Options for Organic Production" (2003). Historical Materials from University of Nebraska-Lincoln Extension. 48. https://digitalcommons.unl.edu/extensionhist/48 This Article is brought to you for free and open access by the Extension at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Historical Materials from University of Nebraska-Lincoln Extension by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. NF585 Bindweed Identification and Control Options for Organic Production By Laurie Hodges, Extension Vegetable Specialist Two species of bindweed are commonly found in the small and green. Each plant can produce 11,000-30,000 Great Plains and one unrelated weed is often confused with seeds between June and September. Although most of the bindweed. Field bindweed (Convolvulus arvensis) is also viable seed will germinate the following year, seeds can known as small morning glory. It has smooth, slender remain viable for about five years. This plant is a strong stems two to seven feet long that twine or spread over the climber and can compete for light in dense crop stands. It soil surface. The leaves are shaped like arrowheads. The can spread rapidly and is highly competitive for moisture white or pale pink flowers are about one inch across. Field and nutrients. Allowing the seeds to germinate prior to bindweed has a deep, extensive root system and is able to tillage provides moderately effective control since it is an persist and thrive with equal ease in uncultivated or most annual weed. It is common in small grain crops, for which crop situations. It is considered one of the most serious there are several chemical controls. It is easier to control weeds in the region and is on the noxious weed list for then field bindweed or hedge bindweed. Colorado, Kansas, South Dakota, Iowa and Missouri, re- quiring whoever owns or manages the land to control this Field Bindweed weed. It is not on the noxious weed list for Nebraska, but is a problem for many growers. Field bindweed is a serious problem for many growers. Hedge bindweed (Calystegia sepium; previously clas- The root system consists of vertical roots extending as sified as Convolvulus sepium) is found throughout the much as 30 feet below ground and shallow, horizontal lateral United States in waste areas and fence rows, but is most roots. The deep vertical roots contribute to the persistence common in the eastern plains states. It is very common in of this weed; however, 70 percent of the root system is in eastern Nebraska. The roots of hedge bindweed are rela- the top 2 feet of soil. Bindweed experiments have provided tively shallow but very extensive. Leaves of this species estimates of bindweed root production of 2.5 to 5 tons per are larger than those of field bindweed and are hairless. acre in one year. Most parts of the bindweed root can Hedge bindweed flowers are 1 1/2 to 2 inches across, white produce adventitious buds, which can create new roots and or pinkish. Each fruit contains a single seed with sharp shoots. Roots capable of budding were found as deep as 14 angles and pointed ends. The stems are smooth and three feet. Fragments of vertical roots as short as two inches can to ten feet long, often twining on other plants or trailing form new plants. At about 15 to 30 inches from the parent along the ground. It is more common on bottom lands than plant, a lateral root may turn downward and become a field bindweed and is less drought tolerant. Under humid secondary vertical root, sending out both roots and shoots conditions, however, it can be a more serious problem than from the turning point. By this means a single field bind- field bindweed. Control practices are similar for both spe- weed plant can spread more than 10 feet in a growing cies of bindweed. season. This extensive underground network allows for Black bindweed or wild buckwheat (Polygonum con- overwintering and persistence of the plant in the soil for volvulus) is often confused with true bindweed; however, many years. it is an annual with slender stems trailing on the ground or Field bindweed is more of a problem in heavy soils but twining about other plants. The leaves are heart-shaped can persist in all soils. Seeds can remain viable in the soil with the basal lobes spreading and a small papery sheath for at least 50 years. Bindweed is relatively easy to control encircles the stem at the leaf base. The flowers are very by cultivation if caught as a very young seedling. However, E-6 once five true leaves have formed (the plant is approxi- of alfalfa puts the bindweed in deep shade. Repeated alfalfa mately six inches long), it develops reproductive buds on cuttings also will reduce the competitiveness of the bind- an extensive root system and becomes extremely difficult to weed. A dense cover crop of red clover (Trifolium pratense) control. Field bindweed is a prostrate plant unless it climbs reduced hedge bindweed biomass but did not eliminate the on an object for support. Under warm, moist conditions, weed in Canadian research. Research indicates that main- leaves are larger and the vines are more robust than under taining dense shade over the bindweed is an important drought conditions. means of using plant competition for control. A crop with An average field bindweed plant produces about 550 early, vigorous growth in the spring may be the best dark brown seeds. Within one month after forming, the seed competitive crop because it forces the bindweed to com- coat matures and becomes impervious to water. Once the pete for light later in the season and reduces available seed coat is weakened by mechanical abrasion in the soil or moisture. Bindweed is very competitive where there are freeze/thaw cycles during the winter, seed will germinate irrigation leaks or other moisture sources. when temperatures range between 41oF and 104oF. Field Seedlings of field bindweed are easy to control with bindweed is drought tolerant and when water is withheld, cultivation, but only for about three to four weeks following bindweed competes better than most other plants. If the seed germination. After that, perennial buds are formed, area is well watered, other plants may compete better than and control is much more difficult. Cultivation or hoeing bindweed. If there is a drought, the plant reduces its seed has been partially effective in reducing established stands production first and then reduces growth and leaf size. of field bindweed. Cultivate every two to three weeks as Some flowers and seeds still will be produced and the roots soon as the bindweed is 6 inches long and repeat whenever can persist. necessary. Withholding irrigation water in summer in con- junction with cultivation may help dry the site. If tillage is Management to be used to control bindweed, some measure of manage- ment can be achieved with repeated tillage if the soil is dry Organic control of field bindweed is not easy, and it each time it’s cultivated. Tillage is most effective when the cannot be accomplished with a single treatment or in a shoots are allowed to grow about 10 days after emergence single season. Effective control requires prevention of from the roots, since they continue to draw resources from seed production, reduction of stored carbohydrates by the rootstock before they can produce new food resources deep tillage of the root system, competition for light from to be stored in the roots. According to one research report, other plants, and constant vigilance in removing top growth. “Sixteen or more cultivations may be needed over a period of several years.” An alternative is a deep cultivation of dry Prevention soil, which “will set back field bindweed enough that it will not interfere with an annual crop.” Deep cultivation means Three practices can reduce the possibility of introduc- using wide sweeps to cut roots and rhizomes 16 to 18 inches ing field bindweed: below the surface in dry soil — not a practical technique for most people, certainly not in the heavy soils of eastern 1. Buy and plant clean seed and ornamental stock. Nebraska. For lighter soils, such as much of the vegetable 2. Remove any seedlings before they become peren- production area in eastern Iowa, deep cultivation may nial plants. provide sufficient control when infestations are low to 3. Prevent any bindweed plants from producing seed. moderate. Black polyethylene mulch has been effective for bind- If topsoil is introduced to a site, it should be free of weed control only if no light is allowed to reach the soil and bindweed vegetative parts and seeds. It is important to the plant. The edges of the plastic must be overlapped so control new infestations when they are small because spot that the bindweed stems cannot grow between the sheets control is least expensive and most effective. and into the light. Landscape fabrics also have been effec- tive if all light is excluded. However, if holes are made in the Cultural Control fabric or plastic for plants, bindweed also can grow through these holes. A landscape fabric placed over soil then Experiments in some annual and perennial crops have covered with bark or other organic matter or rock will demonstrated the effect of shade on bindweed growth.