Triclopyr was first registered for forestry use in 1979 and is currently used in both agricultural and non-agricultural settings. With widespread use, there are over 200 products that contain triclopyr. As always, it is important to read the label, as it is the law and make sure the product you purchase has a forestry label and is labeled for your intended use.
Triclopyr is a systemic herbicide that mimics the plant hormone auxin. This causes uncontrolled, disorganized plant growth, leading to a slow death, typically within weeks. Broadleaf herbs and woody species are the target species, making triclopyr a selective herbicide. There are two basic formulations used in forestry: triethylamine salt (commonly known as Triclopyr 3) and butoxyethyl ester (commonly known as Triclopyr 4). Triclopyr 3 is water-soluble, whereas triclopyr 4 is oil-soluble (bark treatments) and water-soluble (foliar treatments). Triclopyr 4 can volatilize at temperatures above 85° F. Triclopyr 3 does not have that risk. Neither formulation has soil activity.
Triclopyr can be used in all facets of forest management. It is commonly used in site preparation tank mixes, conifer release (directed spray application), mid-rotation vegetation control, and spot treatments for invasive species and other competitive vegetation. With conifer release, one needs to read the label on the application because triclopyr can kill pines. Application techniques range from basal bark, cut-stump, foliar, and hack-and-squirt. For basal bark applications, one would use butoxyethyl ester.
Common Triclopyr Products that Contain a Forestry Label
| triethylamine salt (Triclopyr 3) | butoxyethyl ester (Triclopyr 4) |
| Garlon 3A | Garlon 4 |
| Alligare Triclopyr 3 | Remedy Ultra |
| Vastlan | Pathfinder |
| Alligare Triclopyr 4 | |
| Boulder 6.3 |
As with any herbicide, I would recommend contacting your local Extension Agent. It is important to identify the weeds you want to control, the crop trees you want to protect, and any sensitive areas that do not need to be sprayed.
Author
Jeff Fellers, Cooperative Extension, Forestry and Wildlife Agent
This information is supplied with the understanding that no discrimination is intended and no endorsement of brand names or registered trademarks by the Clemson University Cooperative Extension Service is implied, nor is any discrimination intended by the exclusion of products or manufacturers not named. All recommendations are for South Carolina conditions and may not apply to other areas.
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