A quick guide providing commonly used herbicides used in forest site preparation and release treatments. Tables are broken into (1) conifer site preparation, (2) hardwood plantation site preparation, (3) hardwood natural regeneration site preparation, (4) conifer early release, (5) early hardwood release, (6) cut surface herbicides used for intermediate or crop tree release.
Each table provides the herbicide active ingredient, trade names of labels approved for forestry applications, best time of year to use the herbicide, target species, and species that are resistant to the herbicide. The trade names are linked to the most recent specimen label so users may look up the details of that brand for safety, mixing, and delivery methods. The links use the CDMS database for specimen labels.
Common Herbicides for Conifer Site Preparation
| Active Ingredient | Herbicide Trade Name(s) and Links to Specimen Labels Use to get details of delivery, mix rates, and safety requirements |
Time of Year | Target | Resistant |
|---|---|---|---|---|
| Imazapyr | Arsenal AC, Polaris AC | Summer, in advance of regeneration | Most hardwoods, annual and perennial grasses and forbs, Bermuda, fescue, crabgrass, dog fennel, pigweed, greenbriar, morning glory | Elms, woody legumes, wax myrtle, croton spp., rubus, buckeye, baccharis, pine |
| Imazapyr | Chopper, Polaris SP (surfactant) | Growing season following full leaf expansion | Most hardwoods, annual and perennial grasses and forbs, Bermuda, fescue, crabgrass, dog fennel, pigweed, greenbriar, morning glory | Elms, woody legumes, wax myrtle, croton spp., rubus, buckeye, baccharis, hickory, pine |
| Glyphosate | Accord XRT II, Razor and Razor Pro, Rodeo, Roundup Pro Conc | Prior to planting, active growth following full leaf expansion | Most hardwoods (black locust, persimmon, sassafras, sumac, sweetgum, yellow-poplar) most annual and perennial grasses and forbs | Red maple*, oaks*, ash*, hickory*, dogwood*, rubus, greenbriar, Virginia creeper, trumpet vine |
| Glyphosate and Imazapyr | Prep-It | During periods of active growth | Control most annual and perennial grasses, broadleaf weeds, vines, and woody vegetation | |
| Metsulfuron Methyl | Escort XP, Patriot | During periods of active growth following full leaf expansion | Wide range of annual and perennial broadleaf weeds and woody plants, kudzu, multiflora rose | Grasses, yellow poplar, loblolly pine |
| Sulfometuron Methyl | Oust XP, Spyder | Early spring, before herbaceous weeds emerge or shortly thereafter | Annual grasses and forbs and certain perennial herbs | Bermuda, broomsedge, croton spp., trumper vine, panicums, pines, most hardwoods |
| Sulfometuron Methyl and Metsulfuron Methyl | Oust Extra | After full leaf expansion in spring and before normal defoliation in fall. Herbaceous weeds: apply pre-emergence or shortly thereafter | Various woody plants, vines and herbaceous weeds | Loblolly pine |
| Triclopyr | Element 3A, Garlon 3A, Tahoe 3A, Element 4, Garlon 4 Ultra, Tahoe 4E, Forestry Garlon XRT | During periods of active growth | Most hardwoods, southern pine, waxy species such as bay, gallberry, wax myrtle, and yaupon, forbs, dog fennel, pigweed, greenbriar, and morning glory, rubus | Grasses |
| Aminopyralid | Milestone | Anytime during the growing season. Preferred when weeds are small and actively growing | Rubus, morning glory; horseweed, pigweed, sicklepod, ragweed, wilding pines | Grasses |
| Clopyralid | Clean Slate, Transline | Anytime during the growing season. Preferred when weeds are small and actively growing | certain broadleaf weeds including thistle, kudzu, sicklepod, morning glory, ragweed, coffee weed most legume species | Most established grasses and woody plants |
| Dicamba | Vanquish | During periods of active growth | Many annual and perennial broadleaf weeds, woody brush (including hardwoods and pines), multiflora rose (when dormant) | |
| Fosamine | Krenite S | Apply during the growing season | Postharvest control of pine and hardwood species for southern pine planting site preparation | Non-woody plants (usually) and waxy leafed species |
| Hexazinone | Velpar DF (dispersible granules), Velossa, Velpar L (liquid) | Early spring - early summer after bud break and before hardening off | Most hardwoods, rubus, crabgrass, fescue, lespadeza, horseweed, dog fennel, annual and perennial rye grass | Yellow-poplar, eastern redcedar, sassafras, blackgum, hollies, American beautyberry, Bermudagrass, white snakeroot, broomsedge, Johnsongrass, sicklepod, trumpet vine, morning glory |
| Picloram | Tordon K, Trooper 22K (Restricted Use) | During periods of active growth | Annual and perennial broadleaf weeds, woody plants especially legumes and southern pine speciesand vines | Most grasses are resistant |
| Picloram and 2, 4-D | Tordon 101 M (Restricted Use) | During periods of active growth | Most annual and perennial broadleaf weeds, woody plants, and vines | Most grasses are resistant |
Common Herbicides for Hardwood Plantation Site Preparation
| Active Ingredient | Herbicide Trade Name(s) and Links to Specimen Labels Use to get details of delivery, mix rates, and safety requirements |
Time of Year | Target | Resistant |
|---|---|---|---|---|
| Clopyralid | Clean Slate, Transline | Anytime during the growing season. Preferred when weeds are small and actively growing | Certain broadleaf weeds including thistle, kudzu, sicklepod, morning glory, ragweed, coffee weed most legume species | Most established grasses and woody plants |
| Glyphosate | Accord XRT II, Razor and Razor Pro, Rodeo, Roundup Pro Conc | Prior to planting, active growth following full leaf expansion | Most hardwoods (black locust, persimmon, sassafras, sumac, sweetgum, yellow-poplar) and southern pine, most annual and perennial grasses and forbs | |
| Metsulfuron Methyl | Escort XP, Patriot | During periods of active growth following full leaf expansion | Wide range of annual and perennial broadleaf weeds and woody plants, kudzu, multiflora rose | Most grasses, yellow poplar |
| Sulfometuron Methyl | Oust XP, Spyder | Early spring, before herbaceous weeds emerge or shortly thereafter. Can also be applied in fall prior to planting. | Annual grasses and forbs and certain perennial herbs | Bermuda, broomsedge, croton spp., trumper vine, panicums |
Common Herbicides for Natural Hardwood Regeneration Site Preparation
| Active Ingredient | Herbicide Trade Name(s) and Links to Specimen Labels Use to get details of delivery, mix rates, and safety requirements |
Time of Year | Target | Resistant |
|---|---|---|---|---|
| Glyphosate | Accord XRT II, Foresters, Rodeo | Growing season following full leaf expansion. Broadcast foliar or spray to wet foliage (but not to point of runoff). | Most hardwoods (black locust, persimmon, sassafras, sumac, sweetgum, yellow-poplar), southern pine, most annual and perennial grasses and forbs | |
| Sulfometuron Methyl | Oust XP | Growing season during active herbaceous weed growth. Broadcast foliar application following shelterwood seed cut. | Annual grasses and forbs and certain perennial herbs | Bermuda, broomsedge, croton spp., trumper vine, panicums |
| Glyphosate and Sulfometuron Methyl | Rodeo and Oust XP | Mid summer to early fall. Broadcast foliar application following shelterwood seed cut. | Wide range of annual and perennial broadleaf weeds and woody plants, kudzu, multiflora rose |
Common Herbicides for Early Conifer Release
| Active Ingredient | Herbicide Trade Name(s) and Links to Specimen Labels Use to get details of delivery, mix rates, and safety requirements |
Time of Year | Target | Resistant |
|---|---|---|---|---|
| Imazapyr | Arsenal AC, Polaris AC | Late in second growing season following planting. Broadcast foliar application or directed foliar. | Most hardwoods, annual and perennial grasses and forbs, Bermuda, fescue, crabgrass, dog fennel, pigweed, greenbriar, morning glory | Elms, woody legumes, wax myrtle, croton spp., rubus, buckeye, baccharis, hickory, pine |
| Imazapyr | Chopper, Polaris SP (surfactant) | Late in growing season after formation of final conifer resting bud. Directed foliar spray applications. | Most hardwoods, annual and perennial grasses and forbs, Bermuda, fescue, crabgrass, dog fennel, pigweed, greenbriar, morning glory | Elms, woody legumes, wax myrtle, croton spp., rubus, buckeye, baccharis, hickory, pine |
| Glyphosate | Razor, Rodeo, Roundup Pro Conc | Later summer or early fall, after formation of final conifer resting bud. Broadcast foliar application. | Most hardwoods (black locust, persimmon, sassafras, sumac, sweetgum, yellow-poplar), most annual and perennial grasses and forbs | |
| Metsulfuron Methyl | Escort XP, Patriot | Active growth following full leaf expansion. Herbaceous weeds: apply pre-emergence or shortly thereafter. Broadcast foliar application. | Wide range of annual and perennial broadleaf weeds and woody plants, kudzu, multiflora rose | Grasses, yellow poplar |
| Sulfometuron Methyl | Oust XP, Spyder | Dormant season prior to conifer bud break. Broadcast foliar spray for herbaceous weed control. | Annual grasses and forbs and certain perennial herbs | Bermuda, broomsedge, croton spp., trumper vine, Johnsongrass, panicums |
| Sulfometuron Methyl and Metsulfuron Methyl | Oust Extra | Active growth following full leaf expansion. Herbaceous weeds: apply pre-emergence or shortly thereafter. Broadcast foliar spray, loblolly pine only. | Various woody plants, vines and herbaceous weeds | Conifers somewhat |
| Triclopyr | Element 3A, Garlon 3A, Tahoe 3A, Element 4, Garlon 4 Ultra, Tahoe 4E, Forestry Garlon XRT | During periods of active growth. Directed spray application only. | Most hardwoods, vines, and broadleaf weeds such as dog fennel, pigweed, greenbriar, morning glory | |
| Aminopyralid | Milestone | Spring to late summer: broadcast foliar overtop only on longleaf. Do not use over the top of loblolly or slash pine Directed, spot treatment only. | Broadleaf weeds such as Rubus, morning glory; vetch, horseweed, pigweed, sicklepod, ragweed, and wilding pine suppression | Young longleaf pine |
| Clopyralid | Clean Slate, Transline | Mid to late summer, after conifers have hardened off. Broadcast foliar application made over the top of tolerant tree species or directed spray to wet spot applications for broadleaf weed control. | certain broadleaf weeds including thistle, sicklepod, morning glory, ragweed, coffeeweed, wisteria and kudzuMany legume species | Grasses and many woody plants |
| Hexazinone | Velpar DF (dispersible granules), Velossa, Velpar L (liquid) | Spring after bud break and before full leaf expansion. Broadcast foliar application. | Most hardwoods, rubus, crabgrass, fescue, lespadeza, horseweed, dog fennel, annual and perennial rye grass | Grasses, yellow-poplar, eastern redcedar, sassafras, blackgum, hollies, American beautyberry, Bermudagrass, white snakeroot, broomsedge, Johnsongrass, sicklepod, trumpet vine, morning glory |
Common Herbicides for Early Hardwood Release
| Active Ingredient | Herbicide Trade Name(s) and Links to Specimen Labels Use to get details of delivery, mix rates, and safety requirements |
Time of Year | Target | Resistant |
|---|---|---|---|---|
| Clopyralid | Clean Slate, Transline | Anytime during the growing season. Preferred when weeds are small and actively growing. Broadcast foliar application made over the top of tolerant tree species or directed wet spot applications | many broadleaf weeds such as sicklepod, morning glory, ragweed, coffeeweed, thistle, wisteria, and kudzu | Grasses and most hardwood species |
| Glyphosate | Rodeo, Refuge | Summer, during periods of active growth, after full leaf expansion and before fall color. Directed spot treatments only avoiding contact with desirable species or broadcast during dormant period when hardwood crop trees are dormant. Only certain adjuvants recommended. | Most hardwoods (black locust, persimmon, sassafras, sumac, sweetgum, yellow-poplar) most annual and perennial grasses and forbs | |
| Hexazinone (yellow poplar only) | Velossa, Velpar L | Early spring, after soil has settled around planting slit and before but break. Broadcast foliar application over top of planted seedlings | Most hardwoods, rubus, crabgrass, fescue, lespadeza, horseweed, dog fennel, annual and perennial rye grass | Grasses, yellow-poplar, eastern redcedar, sassafras, blackgum, hollies, American beauty berry, Bermuda grass, white snakeroot, broomsedge, Johnsongrass, sicklepod, trumpet vine, morning glory |
| Metsulfuron Methyl (yellow poplar only) | Escort XP, Patriot | Early spring, after soil has settled around root system and prior to bud break. Herbaceous weeds: apply pre-emergence or shortly thereafter. Broadcast foliar application over top of yellow poplar seedlings only. | Wide range of annual and perennial broadleaf weeds and woody plants, kudzu, multiflora rose | Grasses, yellow poplar |
| Sulfometuron Methyl | Oust XP, Spyder | Early spring, after soil has settled around planting slit and before bud swell stage. Broadcast foliar application over top of planted seedlings | Annual grasses and forbs and certain perennial herbs | Bermuda, broomsedge, croton spp., trumper vine, Johnsongrass, panicums |
Common Herbicides for Cut Surface Methods Used in Intermediate or Crop Tree Release
| Active Ingredient | Herbicide Trade Name(s) and Links to Specimen Labels Use to get details of delivery, mix rates, and safety requirements |
Time of Year | Target | Resistant |
|---|---|---|---|---|
| Aminopyralid and Triclopyr | Capstone | Any season except during spring sap flow. Injection or hatchet frill girdle and spray bottle | Most woody species | |
| Imazapyr | Arsenal AC, Polaris AC | Any season, except during heavy sap flow in spring. Injection or hatchet frill girdle and spray bottle. Non-target injury could result through root grafting. | Many hardwoods | Elms, woody legumes, hickory, pine |
| Glyphosate | Accord XRT II, Razor and Razor Pro, Rodeo, Roundup Pro Conc | During active growth after full leaf expansion. Injection or hatchet frill girdle and spray bottle. | Most woody species including oak, poplar, sweet gum, sycamore; pine | Red maple, hickory, dogwood, black gum |
| Triclopyr | Element 3A, Garlon 3A, Tahoe 3A | Any season, except during heavy sap flow in spring. Injection or hatchet frill girdle and spray bottle. Non-target injury could result through root grafting. | Most woody species | |
| Clopyralid | Clean Slate, Transline | Periods of active growth. Injection or axe frill girdle and spray bottle. Non-target injury could result through root grafting. | Woody legumes | Most hardwoods, pine |
| Dicamba | Vanquish | Any season, except during heavy sap flow in spring. Injection or hatchet frill girdle and spray bottle. | Many hardwoods and pines | Sweetgum, oak, maple |
| Hexazinone | Velossa, Velpar L | Summer. Injector or Hypo-Hatchet. Non-target injury could result through root grafting. | Most hardwoods | Yellow-poplar, eastern redcedar, sassafras, blackgum, hollies, pines, sourwood, dogwood, red maple |
| Picloram and 2,4-D | Pathway (Restricted Use) | Any season, except during heavy sap flow in spring or during periods of drought. Injector or hatchet frill girdle and spray bottle. Non-target injury could result through root grafting. | Most woody plants, and vines |
Publication date: July 14, 2016
Revised: Sept. 1, 2020
Recommendations for the use of agricultural chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by NC State University or N.C. A&T State University nor discrimination against similar products or services not mentioned. Individuals who use agricultural chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. For assistance, contact your local N.C. Cooperative Extension county center.
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This publication printed on: Dec. 21, 2024