J.H. Miller; Manning, S.T; and S.F. Enloe. 2010. A Management Guide for Invasive Plants of Southern Forests. Southern Research Station. Forest Health Protetion. Asheville, NC. 123 p.
Herbicides registered by EPA for forestry use, wildlife openings, noncroplands, and fencerows in the Southern States will mainly be discussed here, although herbicides for other land use areas, such as rights-of-way, pastures, and rangelands, may be just as effective and may contain the same active ingredient. If a herbicide is not prohibited for use on a specific site, crop, or vegetation, then the broad category of noncrop areas even allows use in “nonused” lands and parks in urban and suburban environments. Some prescriptions for these other land types will also be given along with aquatic sites. Carefully read and study the herbicide label for information on specified areas of use, crops, and prohibitions. It is not necessary for the target invasive plant to be listed on the label for permitted use, except in specific States, like New Hampshire. There are a few State-specific prohibitions, such as Florida’s prohibition of picloram herbicides, i.e., Tordon use.
Herbicides are identified by trade name and active ingredient name. Many active ingredients are now sold as generic herbicides at lower costs, while customer service and product liability may be different than the brand name products listed here.
Foliar-Active (Primarily) Herbicides
Enforcer® Brush Killer (triclopyr)
Glyphosate herbicides (glyphosate concentrations commonly range from 41 to 54 percent) such as:
- Accord® Concentrate
- Glyphomax® Plus
- Roundup® Original
- Roundup Pro® Concentrate
- Rodeo® (aquatic)
Garlon® 3A (triclopyr)
Garlon® 4 (triclopyr ester)
Krenite® S (fosamine)
ORTHO® Brush-B-Gon® (triclopyr)
Pathfinder® II (triclopyr in oil)
Renovate® (triclopyr aquatic)
Vine-X® (triclopyr in oil sold in applicator bottle with brush tip)
Foliar and Soil-Active Herbicides
Arsenal® AC (imazapyr)
Arsenal® PowerLine™ (imazapyr)
Chopper® Gen2 (imazapyr)
Clearcast® (imazamox aquatic)
Escort® XP (metsulfuron)
Habitat® (imazapyr aquatic)
Hyvar® X-L (bromacil)
Journey® (imazapic + glyphosate)
Milestone® VM (aminopyralid)
Outrider® (sulfosulfuron)
Overdrive® (diflufenzopyr + dicamba)
Pathway® (2,4-D + picloram)
Plateau® (imazapic)
Tordon® 101 (2,4-D + picloram, Restricted use)
Tordon® K (picloram, Restricted use)
Transline® (clopyralid)
Stalker® (imazapyr)
Vanquish® (dicamba)
Velpar L® (hexazinone)
Because nonnative invasive plants are usually difficult to control, selecting the most effective herbicide(s) is important. Often herbicides that have both soil and foliar activity are most effective with the least number of applications. However, applying herbicides with soil activity can damage desirable plants when their roots are present in the treatment zone or when herbicides move downslope to untreated areas following heavy rainfall. Garlon herbicides are mainly foliar active, but they have some soil activity at high rates or when mixed with oils. Garlon 4 and Vanquish can volatilize or vaporize at high temperatures, and their residues can move by air currents to affect surrounding plants; therefore, avoid application of these herbicides on days when temperatures exceed 80 °F. Avoid applications when rainfall is anticipated, unless soil activation is needed. Consult the label for the rainfast period. Delay applications during severe drought because herbicides are not as effective when plants go into stress dormancy during dry periods.
When possible, use selective herbicides that target specific nonnative species, e.g., Transline, which controls mainly legumes and composites and minimizes damage to surrounding desirable plants even though they receive herbicide contact. Minimizing damage to desirable plants also can be achieved by making applications when they are dormant. For example, apply basal sprays to the bark of invasives in late winter before most other plants emerge, or foliar spray evergreen or semievergreen invasives after surrounding plants have entered dormancy. Remember that desirable woody plants can be damaged through transfer of herbicides by root exudates following stem injection and cut-treat treatments or when soil-active herbicides wash off treated stems. Damage to surrounding native plants can be minimized with care and forethought during planning and application.
