Vine Weeds of Missouri
Fred Fishel and Andy Kendig
Department of Agronomy
Vine weeds are particularly troublesome for many reasons. Their aggressive growth makes timely control with herbicides difficult. Desirable vegetation and wildlife habitat are choked out by their sprawling growth habit. Harvesting efficiency is hindered in agronomic settings because they twine around crop plants. Many of these weeds with a vinelike growth habit are perennials capable of reproducing by seed and vegetative structures, such as rhizomes and vast rootstocks. Some vine weeds even have toxic properties.
Some of these weeds are introduced species that have spread to Missouri from other states. Some are considered to be noxious in Missouri and other states.
These plants have subtle characteristics that separate them from their close relatives or other plants that are similar in physical appearance. Correct identification of vines makes control recommendations more effective because herbicides, application rates and size restrictions can be properly matched.
Use the taxonomic key to identify a suspect vine by the plant's physical features. Then, consult the plant description section for photographs and information about the weed.
This publication is a general reference and does not contain all vines that you may encounter in Missouri. If you need assistance in identifying a weed, submit a sample through your local MU Extension center to the MU Diagnostic Clinic.
Control of vine weeds
The key to control of annual vine weeds is timely application of an appropriate herbicide to small, actively growing weeds. Many annual vines can become difficult to control when they have grown more than 2 inches long. For example, Glyphosate (Roundup-type) herbicides are somewhat weak against morningglory species.
This guide has the latest control recommendations in crop settings.
The key to control of perennial vines is application of systemic herbicides when plants are fully leaved and are sending sugars down to root systems in preparation for winter. This downward movement of sugars helps carry the herbicides into the root system.
A common mistake is applying herbicides too early when relatively few weeds are present or when food reserves are moving upward from the roots. In this case, the leaf area limits the amount of herbicide that enters the plant, or the upward movement of sugars limits movement of the herbicides into the roots.
Conversely, herbicides are sometimes applied too late when the aboveground parts of the plant have stopped active growth. The ideal time to apply herbicides to perennial weeds is usually immediately after bloom. For many weeds, this corresponds to late summer to early fall.
With easier-to-control perennials, timing is less critical, and good results can be obtained with relatively few herbicide applications. Difficult perennials require repeated herbicide applications over many years.
In row crops, intensive tillage tends to disrupt perennial weeds; moderate tillage tends to help spread perennial weeds; and no tillage favors perennial growth but will actually limit spread. Tillage implements can break roots and rhizomes and drag them to new locations where they can establish new patches of the particular weed.
Generally, products in which 2,4-D is the only active ingredient can provide good control of easier-to-control perennials. However, the more expensive brush killers, containing dicamba (Banvel, Clarity and others), picloram (Tordon) and triclopyr (Crossbow), are needed for the more difficult species. Many mixtures are available.
Glyphosate provides excellent control of some perennial weeds, but it is weaker on others. Be sure to read the product labels and to match herbicides to the vine species.
In row crops, dicamba-based herbicides (Banvel, Clarity and others) typically provide the best control of difficult perennials. Unfortunately, dicamba is not registered for preharvest use in soybean or cotton; however, it is registered for preharvest application in corn.
Perennial control recommendations usually call for high herbicide application rates that result in expensive treatments. It is rarely economical to treat entire fields for difficult perennials, especially since single applications are unlikely to provide complete control.
In most cases, spot applications should be made if possible. Products in which 2,4-D is the only active ingredient can provide excellent control of the easier-to-control annuals.
Control of perennial vines in agronomic crops is difficult. Long-term studies indicate that glyphosate in Roundup Ready crops will provide some perennial suppression; however, the major limitation is that glyphosate must be applied early for adequate control of annuals. Typically, those applications are too early for optimal perennial control. Dicamba is registered for preharvest and postharvest applications in corn (and grain sorghum), and you should consider planting these crops if perennials are a problem.
Before using any herbicide
Read and follow directions on the label accompanying that product. Reference to specific trade names does not imply endorsement by MU; discrimination is not intended against similar products.
IPM1021, new December 2003