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Imazapyr 4 SL Herbicide

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Imazapyr 4 SL Herbicide is a pre-emergent and post-emergent bare ground herbicide for control of unwanted vegetation in non-cropland areas and aquatic sites. It will sterilize the soil it is sprayed over and nothing will grow for up to 1 year. Imazapyr Can also be used in pastures, rangelands and other listed areas.

Target Pests

Imazapyr 4 SL Herbicide can control grasses such as bluegrass bahiagrass barnyardgrass bermudagrass cattail crabgrass dallisgrass fescue goosegrass itchgrass johnsongrass lovegrass kentucky bluegrass saltgrass sandbur wild barley wild oats witchgrass and other listed grasses.

Imazapyr 4 SL Herbicide can control broadleaf weeds such as bull thistle burclover carpetweed chickweed clover ragweed dandelion dock fiddleneck goldenrod henbit horseweed kochia milkweed pigweed primrose smartweed sorrell sowthistle spurge sunflower wild carrot wild lettuce yellow woodsorrell and other listed weeds.

Imazapyr 4 SL Herbicide can also control vines and brambles woody brush and certain trees as well as aquatic weeds.

For Use In

Imazapyr 4 SL Herbicide is for use in non-croplands such as utility pipeline railroad utility plant sites highway rights-of-way petroleum tank farms fence rows storage areas pumping installations non-irrigation ditchbanks under paved surfaces rangeland and grass pastures.


For a broadcast low volume foliar application mix at a rate of 1 1/3-6 2/3 ounce Imazapyr plus 1/3 ounce of non-ionic surfactant per gallon of water. Imazapyr 4 SL Herbicide should be used at a rate of 1-3 pints per acre for control of grassy and broadleaf weeds.

For aquatic treatment use Imazapyr 4 SL Herbicide at a rate of 0.5-1.5 pints per acre. Not to exceed 1.5 pints per acre per year.

Coverage Area

Coverage area of Imazapyr 4 SL Herbicide varies depending on application but not to exceed 3 pints per acre per year.

Time to Kill

Imazapyr 4 SL Herbicide begins to eliminate unwanted weeds within turf just after application but can take up to several weeks to completely kill of the target weeds.

Mix Rate

Mix at a rate of 1 1/3-6 2/3 ounce Imazapyr plus 1/3 ounce of non-ionic surfactant per gallon of water.

Active Ingredient

Isopropylamine salt of Imazapyr 52.6%

Imazapyr 4 SL Herbicide

Imazapyr 4 SL Herbicide

Imazapyr 4 SL, with Imazapyr 52.6% is a broad-spectrum, pre and post-emergent spray for control of most broadleaf weeds, vines, brambles, annual and perennial grasses, trees for forestry site preparation, hardwood brush, and release of conifers from woody and herbaceous competition. It is used for bare ground control of unwanted vegetation, sterilizing the soil it is sprayed over for up to a year. Compare Imazapyr 4 SL to Arsenal AC

Why Imazapyr Is So Effective

Vegetation absorbs Imazapyr through the roots and foliage. It moves throughout the plant causing chlorosis (a yellowing of plant tissues). Afterward, tissue necrosis is spread throughout. After application, Alligare Imazapyr 4 SL moves to the roots of the plant and kills the roots and underground storage tissue and prevents most emerging growth. The tissue necrosis and chlorosis may appear for several weeks in some plant species. It may take months for woody plants, brush, and trees to show the necrosis or chlorosis.




In any vegetation management program, sometimes you need total elimination of vegetation, especially when it comes to bare ground control.


Luckily, At Solutions Pest and Lawn, you can find a large selection of products that are used by both lawn care management professionals and industrial vegetation management technicians that will completely eliminate all vegetation.


In our store, you can find products ranging from pre-emergent herbicides to aquatic herbicides, to bare ground and industrial vegetation management products that will help you clear out invasive species of vegetation in industrial sites such as lumberyards and railroad tracks.


One of these products that is perfect for a variety of uses, including bare ground treatment, forestry preparation, and aquatic sites is Imazapyr 4 SL that controls more than 170+ species of weeds, including trees!


Purchase Imazapyr 4 SL today and get free shipping! Perfect for bare ground and industrial vegetation management programs




  • Created by Alligare, who specializes in vegetation management in a number of sites that include, railroad, range and pasture, forestry, and aquatic sites, every product you get is developed hand-in-hand with university personnel to bring you market-based solutions that yield incredible results.


  • This powerful pre-emergent and post-emergent terrestrial and aquatic herbicide will provide total elimination of targeted weeds including trees.


  • Compromised of 52.6% Isopropylamine salt of Imazapyr, this active ingredient is absorbed through foliage and roots and is translocated throughout the plant where it causes necrosis and kills underground storage tissues preventing regrowth.


  • It is extremely versatile as it can be used in a number of applications, in aquatic sites, in cut and stem treatments, in forestry site preparation, and to control forest roads of undesirable vegetation.


  • This incredibly potent broad-spectrum product targets more than 170+ species of vegetation including annual and perennial grasses, broadleaf weeds, vines, brambles, hardwood brush, aquatic weeds, and trees.


  • This product will control all undesirable vegetation in about 4 to 6 weeks.


  • This product can also be used as an aquatic herbicide and has no restrictions on the use of water in treatment areas for recreational purposes including swimming and fishing.


  • There are also no restrictions on livestock water consumption in the treated body of water.


  • This product comes in three sizes a 32-ounce bottle for residential jobs, a 1-gallon jug for commercial sites, and a 2.5-gallon jug for larger industrial sites.




This product is registered in the following States – AK, AL, AR, AZ, CA, CO, CT*, DE, FL, GA, HI, IA, ID, IL, IN, KS, KY, LA, MA, MD, ME, MN, MO, MS, MT, NC, ND, NE, NH, NJ, NM, NV, NY, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VT*, VA, WA*, WI, WV, WY


*State Restricted Pesticide


This product is labeled to be used in for the control of undesirable vegetation in forestry sites, aquatic sites, grass pasture, fence rows, maintenance of wildlife openings, and industrial non-croplands areas including railroad, utility, pipeline right-of-way, utility plant sites, petroleum tank farms, pumping installations, storage areas, building perimeters, irrigation and non-irrigation ditch banks, roads, transmission lines, and industrial bare grounds.


This product can also be used as an aquatic herbicide for the control of undesirable emergent and floating aquatic vegetation in and around standing and flowing water, including estuarine and marine sites. Application to public waters can be made. 


Consult local state fish and game agency and water control authorities before applying this product to public water. Permits may be required to treat such waters.


In the State of New York, aquatic uses are not allowed. 




This product is labeled to control annual and perennial grasses that include Annual bluegrass, Bahiagrass, Barnyardgrass, Beardgrass, Bermudagrass, Big bluestem, Broadleaf signalgrass, Canada bluegrass, Cattail, Cheat, Cogongrass, Crabgrass, Crowfootgrass, Dallisgrass, Downy brome, Fall panicum, Feathertop, Fescue, Foxtail, Giant reed, Goosegrass, Guineagrass, Italian ryegrass, Itchgrass, Johnsongrass, Junglerice, Kentucky bluegrass, Lovegrass, Orchardgrass, Panicum spp. Paragrass, Phragmites, Prairie cordgrass, Prairie threeawn, Quackgrass, Reed canarygrass, Saltgrass, Sand dropseed, Sandbur, Smooth brome, Sprangletop, Timothy, Torpedograss, Vaseygrass, Wild barley, Wild oats, Wirestem muhly, Witchgrass, and Woolly cupgrass.


This product is also labeled to control annual and perennial broadleaf weeds including, Arrowwood, Broom snakeweed, Bull thistle, Burclover, Burdock, Camphorweed, Canada thistle, Carolina geranium, Carpetweed, Chickweed, Mouseear Chickweed, Clover, Cocklebur, Common chickweed, Common ragweed, Cudweed, Dandelion, Desert camelthorn, Diffuse knapweed, Dock, Dogfennel, Fiddleneck, Filaree, Fleabane, Giant ragweed, Goldenrod, Gray rabbitbrush, Henbit, Hoary vervain, Horseweed, Indian mustard, Japanese bamboo/knotweed, Knotweed, Knotweed prostrate, Kochia, Lambsquarters, Little mallow, Milkweed, Miners lettuce, Mullein, Nettleleaf goosefoot, Oxeye daisy, Pepperweed, Pigweed,  Plantain, Pokeweed, Primrose, Puncturevine, Purple loosestrife, Purslane, Pusley, Florida Pusley, London Rocket, Rush skeletonweed, Russian knapweed, Russian thistle, Saltbush, Shepherd’s purse, Silverleaf nightshade, Smartweed, Sorrell, Sowthistle, annual Spurge, Stinging nettle, Sunflower, Sweet clover, Tansymustard, Texas thistle, Velvetleaf, Western ragweed, Wild carrot, Wild lettuce, Wild parsnip,  Wild turnip, Woollyleaf bursage, Yellow starthistle, and Yellow woodsorrel.


This product is also labeled to control the following species of vines and brambles including Field bindweed, Hedge bindweed, Honeysuckle, Morningglory, Poison ivy, Redvine, Trumpetcreeper, Virginia creeper, Wild buckwheat, Wild grape, and Wild rose (Including Multiflora rose, Macartney rose).


This product can also treat the following species of trees and woody brush including Alder, American beech, Ash, Aspen, Autumn olive, Bald cypress, Bigleaf Maple, Birch, Black oak, Blackgum, Boxelder, Brazilian peppertree, Ceanothis, Cherry, Chinaberry, Chinese tallow-tree, Chinquapin, Cottonwood, Cypress, Dogwood, Eucalyptus, Hawthorn, Hickory, Huckleberry, Lyonia (Including Fetterbush and Staggerbush), Madrone, Maple, Melaleuca, Mulberry, Oak, Persimmon, Poison oak, Popcorn-tree, Poplar, Privet, Red Alder, Red Maple, Saltcedar, Sassafras, Sourwood, Sumac, Sweetgum, Sycamore, Tanoak, TiTi, Tree of heaven, Vaccinium (Including Blueberry and Sparkleberry), Willow,  and Yellow poplar. 


This product is also labeled to control the following species of aquatic, terrestrial, marginal and floating vegetation that include Duckweed, Giant Duckweed, Frogbit, Spatterdock, Water Hyacinth, Water Lettuce, Alligatorweed, Arrowhead, Duck-potato, lemon Bacopa, Parrot Feather, Pennywort, Pickerelweed, Wild Taro, Dasheen, Elephant’s ear, Coco Yam, Water lily, Water primrose, Soda Apple, Nightshade Aquatic, Japanese Bamboo, Brazilian Pepper, Christmasberry, Cattail, Chinese Tallow tree, Cogongrass, prairie Cordgrass, Cutgrass, Elephant grass, Napier Grass, Flowering Rush, Ginat Reed, Wild Cane, Golden Bamboo, Junglerice, Knapweeds, Japanese Knotweed, Melaleuca, Paperbark Tree, Nutgrass, Kili’p’opu, Nutsedge, Phragmites, Common Reed, Poison Hemlock, Purple Loosestrife, Reed canarygrass, Swamp Rose, Russian-Olive, Saltcedar, Tamarisk, Smartweed, Sumac, Swamp Morning Glory, Water Spinach, Kangkong, Torpedo Grass, White Top, Hoary Cress, and Willow.




Remember that it is the law to read the whole label including instructions, precautions, and warnings before using or mixing this product, and always remember to wear the mandatory personal protective equipment stated on the label (click here to buy personal protective equipment).


Remember that this is a very powerful bare-ground herbicide that may affect untreated desirable plants by root uptake of treated soil or through movement into the topsoil. Injury or loss of desirable plants may result if this product is applied on or near desirable plants, on areas where their roots extend. Remember to exercise extreme caution when spraying this product and consult the spray drift management portion of this label before applying.


As this product targets a variety of vegetation (more than 170+ species) you can find detailed instructions on the label for each use (including stump and cut stem treatments, use on forestry sites preparation, for bare-ground management, aquatic application uses, or for spot treatment of undesirable hardwood vegetation, and rangeland use) species of vegetation you are looking to control, consult the label before applying. 


This product can be applied with a backpack, tank mix, or hand sprayers. Our easy to use and convenient Solutions 1 Gallon Pump Sprayer with lifetime warranty would be ideal (you can buy it here) for smaller applications or you can browse our professional tank and backpack sprayers here



This product can be applied through aerial application for both land and aquatic applications (aerial application in aquatic use is restricted to only helicopter) to apply in this manner check the label for detailed instructions and requirements. 


Postemergence applications of this product may require an addition of a spray adjuvant for best results. Remember to check the partner labeling of all tank-mix partners for requirements of compatibility. For the types of adjuvants you can use alongside this product, along with their ratios, consult the label. 


To use this product as a spot treatment and broadcast treatment with a handheld sprayer apply at a rate of 1 gallon of water per 1- 1/3 ounces to 6-2/3  ounces of the product depending on desired concentration of product (check the label’s mixing rate application table for detailed instructions)  wanted, along with 1/3 ounces of a nonionic surfactant. Only use 5 to 100 gallons of finished water per acre. 


For surface treatments in aquatic areas apply this product at a rate of 1 to 3 pints per acre depending on the species of aquatic weed you wish to control (consult the label for species and rates you want to control). Do not exceed the maximum label rate of 3 pints per acre.


When an application is made to aquatic sites oxygen depletion may occur in the water due to decaying vegetation. To prevent this treat only one half of the surface area in a single application and wait 10 to 14 days to finish treatment to the other half.


To apply this product for control of undesirable weeds in paved surfaces apply at a rate of 3 pints per acre (or 1.1 fluid ounces per 1000 square feet) mixed with clean water.


To use this product for total vegetation control where bare ground is desired this product can be used alone at a rate of .75 to 3 pints per acre or alongside herbicides in the tank mix that include Diuron, Simazine, Vanquish, and other registered herbicides labeled for this use. 




This incredibly versatile pre-emergent and post-emergent herbicide product has a large number of uses, including the control of aquatic weeds, and targets more than 170+ species of weeds and trees.


Used for complete elimination in vegetation management programs, it is ideal for forestry preparation and to clear industrial sites of invasive weeds.


It’s active ingredient of 52.6% Isopropylamine salt of Imazapyr, translocates throughout the targeted plants stopping growth and eliminating them in a matter of weeks.


If you’re looking for a bare ground management herbicide for complete vegetation elimination, this extremely potent product is the one that you’re looking for.


Purchase Imazapyr 4 SL Today and Get Free Shipping! An Excellent Choice for Bare Ground Control.


Product Q & A

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What is the difference between Imazapyr 2sl and Imazapyr 4sl?
Eddy on Nov 3, 2016
BEST ANSWER: Difference between Imazapyr 2sl and Imazapyr 4sl is that the 2SL stands for 2lbs of active ingredients vs the 4SL, which is 4 lb's active ingredients.
If imazapyr 4 sl is double the strength of 2sl why are the mixing rate tables the same on the label ?
A shopper on Jul 24, 2018
BEST ANSWER: The application will vary depending on the targeted weed and the area of application. They will look similar but you will use less of the 4sl compared to the 2sl.
Is it harmful to wild life? Or dogs?
A shopper on Aug 8, 2018
BEST ANSWER: The product is hazardous to domesticated animals. Please exercise caution and apply according to label directions.
Will this kill Japanese Knotweed?
WV_Axeslinger on Jul 20, 2018
BEST ANSWER: Alligare Imazapyr 4 SL provides postemergence control and some residual control of the following
target weed species. The degree of control is both species and rate dependent. Use
Alligare Imazapyr 4 SL only in accordance with the directions on this label.

Yes, it does list Japanese Knotweed on the label as a weed controlled.
will this kill Matgrass
butch on Jun 4, 2017
BEST ANSWER: Matgrass is not listed as a controlled weed on the Imazapyr label, you can spot treat with Glyphodsate.

Impacts: Matgrass is an uncommon non-native grass with the potential to
out-compete desirable grasses and forbs Because it is a species of low
palatability it is not favored by grazing livestock or wildlife giving matgrass
a competitive edge. Impacts to coastal habitats are less well known, but
early surveys reveal an aggressive invader that pushes out native
flora. One of the challenges in controlling matgrass is identifying it amongst
other native or desirable forage species. Untreated plants develop seeds
and perpetuate infestations for decades
If used as a spot treatment, is it as likely to affect trees nearby thru root transmission? We have limited amounts of Japanese knotweed on a berm area we'd like to sod. There are larger plants on the back of the berm which will require more intense treatment.
Jan K on Aug 12, 2018
BEST ANSWER: Careful spot treatment should minimize the chances that nearby trees are affected. Please check the label for more details on preventing desired trees and plants from being damaged.
Will Imazapyr kill phragmites?
A shopper on Jul 20, 2018
BEST ANSWER: The species of annual and perennial grasses controlled by Alligare Imazapyr 4 SL include
the following:
Annual bluegrass (Poa annua)
Bahiagrass (Paspalum notatum)
Barnyardgrass (Echinochloa crus-galli)
Beardgrass (Andropogon spp.)
Bermudagrass (Cynodon dactylon)
Big bluestem (Andropogon gerardii)
Broadleaf signalgrass (Brachiaria platyphylla)
Canada bluegrass (Poa compressa)
Cattail (Typha spp.)
Cheat (Bromus secalinus)
Cogongrass (Imperata cylindrica)
Crabgrass (Digitaria spp.)
Crowfootgrass (Dactyloctenium aegyptium)
Dallisgrass (Paspalum dilatatum)
Downy brome (Bromus tectorum)
Fall panicum (Panicum dichotomiflorum)
Feathertop (Pennisetum villosum)
Fescue (Festuca spp.)
Foxtail (Setaria spp.)
Giant reed (Arundo donax)
Goosegrass (Eleusine indica)
Guineagrass (Panicum maximum)
Italian ryegrass (Lolium multiflorum)
Itchgrass (Rottboellia exaltata)
Johnsongrass (Sorghum halepense)
Junglerice (Echinochloa colonum)
Kentucky bluegrass (Poa pratensis)
Lovegrass (Eragrostis spp.)
Orchardgrass (Dactylis glomerata)
Panicum spp.
Paragrass (Brachiaria mutica)
Phragmites (Phragmites australis)
Prairie cordgrass (Spartina pectinata)
Prairie threeawn (Aristida oligantha)
Quackgrass (Agropyron repens)
Reed canarygrass (Phalaris arundinacea)
Will this kill tomatoes?
Nicole R on Jul 20, 2018
BEST ANSWER: Yes, Imazapyr 4 SL will kill tomato plants.
What is the recommended mixing ratio for small tank sprayer (16 gal) when this is used for bare ground applications?
Ampped on Jan 7, 2018
This product is an effective herbicide for preemergence or postemergence control of many annual
and perennial broadleaf and grass weeds where bare ground is desired. This product is
particularly effective on hard-to-control perennial grasses. This product at 0.75 to 3 pints per acre
can be used alone or in tank mix with Diuron, Simazine, Vanquish®, or other registered herbicides
labeled for this use. The degree and duration of control are dependent on the rate of this product
used, tank-mix partner, the volume of carrier, soil texture, rainfall and other conditions.

About 1.11 ounce at the high rate per 1,000 square feet, you would want to apply with 2 gallons of water.

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