Trimec is a postemergent, selective herbicide used for controlling broadleaf weeds in turfgrass. It is manufactured by PBI-Gordon and is widely used in both residential and commercial lawn care.
Contents
Common Trimec Herbicide Formulations
There are several formulations of Trimec herbicides, each tailored to specific applications and grass types.
When selecting a Trimec herbicide, you must take into consideration the grass type to ensure the product is safe for your specific turfgrass species, the target weeds, the application scale, and the desired speed of results.
Trimec Classic Broadleaf Herbicide
This is the original formulation, effective against over 90 broadleaf weeds, including dandelion, clover, plantain, and chickweed. It’s suitable for various turfgrass species like fescue, bluegrass, ryegrass, bermudagrass, zoysiagrass, and bahiagrass.
Trimec 992 Broadleaf Herbicide
Designed for professional use, Trimec 992 offers a higher concentration for large-scale applications. It provides effective control of hard-to-kill broadleaf weeds and is suitable for use on both cool- and warm-season grasses.
Trimec Southern Broadleaf Herbicide
Formulated specifically for sensitive southern grasses like St. Augustine and centipedegrass, this version controls tough weeds without harming these grass types.
Trimec Lawn Weed Killer
A consumer-grade product available in various sizes, it’s designed for homeowners to control over 230 listed broadleaf weeds without damaging most lawn grasses when used as directed.
Trimec Speed Lawn Weed Killer
This formulation offers faster visual results, often within hours of application, making it ideal for those seeking quick weed control.
Trimec Crabgrass Plus Lawn Weed Killer
Combines broadleaf weed control with crabgrass prevention, offering a more comprehensive solution for lawn care.
Trimec 899 Broadleaf Herbicide
A professional-grade product that controls a wide range of broadleaf weeds and is suitable for use on various turfgrass species.
| Product Name | Key Features | Weeds Controlled | Coverage |
|---|---|---|---|
| Trimec Classic | Original 3-way broadleaf herbicide; industry standard | 90+ broadleaf weeds (e.g., dandelion, clover) | Not specified |
| Trimec 992 | Economical, fast-acting; professional use | 90+ broadleaf weeds (e.g., clover, plantain) | Not specified |
| Trimec Lawn Weed Killer | Consumer-grade concentrate; economical for large areas | 230+ broadleaf weeds | 32,000–64,000 sq. ft. (2,973–5,946 sq. m.) per gallon |
| Trimec Speed | Fast visual results in as little as 8 hours | 250+ broadleaf weeds | Up to 10,600 sq. ft. (985 sq. m.) per quart |
| Trimec Southern | Formulated for sensitive southern grasses | Broadleaf weeds | Not specified |
| Trimec Crabgrass Plus | Controls emerged crabgrass and 200+ broadleaf weeds | Crabgrass, foxtail, signalgrass, broadleaf weeds | Up to 5,000 sq. ft. (465 sq. m.) per quart |
| Trimec Platinum All-In-One | Controls crabgrass and broadleaf weeds | Crabgrass, broadleaf weeds | Not specified |
| Trimec Encore | Enhanced formula with added actives for tough weeds | Broadleaf weeds | Not specified |
| Trimec 1000 Low Odor | Low-odor formulation for sensitive areas | Broadleaf weeds | Not specified |
| Trimec Bentgrass Formula | Specifically formulated for bentgrass turf | Broadleaf weeds | Not specified |
Active Ingredient
Not all Trimec herbicides contain the exact same active ingredients, though many share a core combination.
The core Trimec formula includes a 3-way mix of active ingredients: 2,4-D, MCPP or MCPA (Mecoprop), and Dicamba. This formulation is used in products such as Trimec Classic, Trimec 992, and Trimec Lawn Weed Killer.
These ingredients act like plant hormones and disrupt the weed’s growth system. This causes the weeds to grow abnormally from twisting, swelling, and eventually breaking until they die. 2,4-D and MCPP mainly affect the leaves and stems, while Dicamba also moves into the roots, helping to kill the entire plant. Together, they control many types of weeds and work more effectively than a single ingredient alone.
You can typically see the first visible results from this herbicides within 2 to 3 days after application. Still, the full effect takes 7 to 14 days, depending on weather conditions and weed type.
The other herbicides specialized products include additional or different active ingredients, such as:
- Trimec Crabgrass Plus / Platinum: Adds quinclorac for grassy weed control.
- Trimec Speed: Includes carfentrazone-ethyl, a fast-acting contact herbicide.
- Trimec Southern: Uses lower concentrations and adjusted ratios to reduce risk to sensitive southern grasses.
- Trimec Encore: Contains upgraded versions or additional ingredients for enhanced weed control.
- Trimec 1000 Low Odor: Similar active ingredients but reformulated for lower odor emission.
Approved Application Areas
Trimec herbicide can be used on turfgrass in a wide variety of places. It’s suitable for lawns and grassy areas in homes, apartment complexes, schools, parks, sports fields, office buildings, hospitals, and similar locations.
You can apply it around houses, public buildings, retail spaces, and even on golf courses or cemeteries. It is meant for use by people who manage lawns professionally, such as landscapers and groundskeepers.
What weeds does this herbicide control or suppress?
This herbicide controls broadleaf weeds, which are weeds with wide, flat leaves and distinct veins.
It does not target grassy weeds like crabgrass unless in special formulations like Trimec Crabgrass Plus.
It typically controls over 200 species of broadleaf weeds, depending on the specific Trimec product.
| annual fleabane | aster, white heath & white prairie | bedstraw | beggarticks |
| beggarweed, creeping | bindweed | birdsfoot trefoil | black medic |
| broadleaf plantain | buckhorn plantain | bull thistle | burclover |
| burdock, common | buttercup, creeping | Carolina geranium | carpetweed |
| chickweed, common | chicory | cinquefoil | clover |
| cocklebur | compassplant | curly dock | dandelion |
| dayflower | deadnettle | dock | dogfennel |
| dovefoot geranium | English daisy | false dandelion (*spotted catsear & common catsear) | field bindweed (*morningglory & creeping jenny) |
| field madder | field oxeye-daisy (*creeping oxeye) | field pennycress | filaree, whitestem & redstem |
| Florida pusley | ground ivy | groundsel | hairy bittercress |
| hawkweed | healall | henbit | horsenettle |
| horseweed | innocence (Blue-eyed Mary) | jimsonweed | kochia |
| lambsquarters | lawn burweed | lespedeza, common | mallow, common |
| matchweed | mouseear chickweed | mustard | nettle |
| old world diamond flower | Oxalis (*yellow woodsorrel & creeping woodsorrel) | parsley-piert | Pennsylvania smartweed |
| pennywort (*dollarweed) | pepperweed | pigweed | pineappleweed |
| plantain | poison ivy | poison oak | prostrate knotweed (*knotweed) |
| puncturevine | purple cudweed | purslane | ragweed |
| redweed | red sorrel (*sheep sorrel) | roundleaf greenbriar | shepherd’s purse |
| spotted spurge | spurge | sunflower | thistle |
| velvetleaf (*buttonweed) | Venice mallow | Veronica (*corn speedwell) | Virginia buttonweed |
| Virginia-creeper | western salsify | white clover (*Dutch clover, honeysuckle clover, white trefoil & purplewort) | wild carrot |
| wild garlic | wild geranium | wild lettuce | wild mustard |
| wild onion | wild strawberry | yarrow | yellow rocket |
Application Timing
This herbicide can be used on both cool-season and warm-season grasses in lawns and sod farms.
For best results, apply it in spring or early fall when weeds are actively growing. When planning the application time, you also need to consider the weather and watering conditions.
You should not apply it during very hot or dry weather unless you can water the area.
After application, do not water the grass within 24 hours, and wait until the grass has been mowed two or three times before applying it to new lawns.
You can plant new grass 3 to 4 weeks after application.
Application Rate Trimec Classic
In the case of general use on cool-season grasses, common bermudagrass, bahiagrass, or zoysiagrass, you can apply 3.25 to 4.0 pints per acre (3.8 to 4.7 liters per hectare) in 20 to 260 gallons (75 to 985 liters) of water. Alternatively, you can use 1.2 to 1.5 fluid ounces (35 to 44 milliliters) per 1,000 square feet (93 square meters) in 0.5 to 6 gallons (1.9 to 22.7 liters) of water. For clover, the best time to spray is in the fall. In spring, use 4 pints per acre (4.7 liters per hectare) for best control.
For hybrid bermudagrass, you should use 2.0 to 4.0 pints per acre (2.4 to 4.7 liters per hectare) in 20 to 260 gallons (75 to 985 liters) of water, or 0.75 to 1.5 fluid ounces (22 to 44 milliliters) per 1,000 square feet (93 square meters) in 0.5 to 6 gallons (1.9 to 22.7 liters) of water.
For bentgrass, centipedegrass, and St. Augustinegrass, on low-mowed bentgrass (such as golf greens), use 1.0 fluid ounce (29.6 milliliters) per 1,500 square feet (139 square meters) in 5 gallons (18.9 liters) of water. You should expect slight yellowing, which fades after about a week. For centipedegrass and St. Augustinegrass, it’s safer to spot spray only the weeds. Keep in mind to not apply on St. Augustinegrass during spring green-up, and never use it on the ‘Floratam’ variety.
How to Apply It
Here are clear and practical step-by-step instructions for applying this herbicide safely:
- The first step when you decide to apply the herbicide is to check the weather. You have to make sure you choose a dry day with mild temperatures between 60–77°F (15–25°C). Avoid days with strong wind, rain forecast within 24 hours, or extreme heat or drought. Also, do not try to apply this herbicide if the grass is wet from dew or rain.
- The second step is to prepare the proper protective clothing. You need a long-sleeve shirt, long pants, chemical-resistant gloves, safety goggles or glasses, and closed-toe shoes or rubber boots.
- Then, read the label carefully and follow the specific mixing instructions, application rates, safety information, and any grass types or areas to avoid.
- Before mixing, make sure not to prepare more herbicide solution than you need. Excess herbicide is difficult to dispose of safely and may pose environmental risks. Always calculate the right amount based on the size of the area you plan to treat.
- After all this, you can start mixing the herbicide correctly. You should have all necessary items within your reach and begin by mixing the herbicide and water in the correct ratio, based on spray volume per acre, target weed type, and weed size. Stir or shake the solution well for even mixing. Always use clean equipment like a handheld, backpack, or tank sprayer.
- After the solution is ready, you can start spraying the herbicide. Spray evenly across the lawn or target area, making sure to cover the weeds thoroughly. Try not to overapply. Use just enough to wet the leaves, not to the point of runoff.
- After you finish, clean your sprayer thoroughly with water. Then wash the rest of the equipment. Always wash your protective clothing separately from other laundry.
- If you have leftover herbicide concentrate (not mixed with water), store it in its original container with the label intact. Keep it tightly sealed in a cool, dry, and well-ventilated area, away from direct sunlight, food, and animal feed. Never store herbicides in unlabeled or food containers.
- As post-application care, do not water the lawn for at least 24 hours after spraying, and avoid mowing for 2 to 3 days after application.
Guidelines for Using This Herbicide in Non-Crop Areas
This herbicide can be used in areas where crops are not grown. Do not use it on trees or plants that are grown for sale, for seed production, or for research purposes.
To control brush (woody plants), you need to spray all parts of the plant from leaves, stems, and shoots until they are wet down to the ground. The best time to spray is from spring, when the plants have all their leaves, until they start going dormant. The herbicide works best on young and actively growing weeds and brush.
Do not cut or mow the brush or weeds right after spraying. You need to wait until the herbicide moves through the plant and kills the roots.
For annual and perennial weeds, only spray after the weeds have emerged. Apply when the weeds are young and actively growing for the best results. You can use up to 1 gallon per acre (3.8 liters per 0.4 hectares) in a single application.
A maximum of 2 applications is allowed per year. You must use at least 2 gallons (7.6 liters) of total spray solution per acre.
| Target species | Annual and perennial weeds | Woody plants |
| Application schedule | Broadcast | Broadcast and high volume foliar |
| Maximum application rate, Gallons of product per acre | 1.0 gal/A | 2.0 gal/A |
| Maximum application rate, Pounds of 2,4-D acid equivalent per acre per application | 2.0 lb/A | 4.0 lb/A |
| Maximum number of applications per year | 2 | 1 |
| Minimum days between applications | 30 days | — |
| Minimum spray volume, gallons per acre | 2 | NA |
High-volume foliar applications (100 to 400 gallons per acre / 380 to 1,500 liters per hectare)
Apply 0.5 to 2.0 gallons (1.9 to 7.6 liters) of product per acre, mixed with enough water. You can also use a spray solution with 0.5% to 2.0% herbicide mixed into water and apply it as a full spray using high-volume equipment.
Use the lower concentration for easier-to-kill plants, and the higher concentration for tough weeds, mature plants in late summer, or when the weather is not ideal (like during drought).
Spray broadleaf weeds, woody plants, or brush evenly and completely. Make sure all parts of the plants like leaves, stems, bark, and base of the stems, are wet.
The total amount of spray liquid needed to fully cover thick brush areas can be between 100 and 400 gallons (380 to 1,500 liters) per acre.
| Spray Solution per Acre (Gallons) | 100 | 200 | 300 | 400 |
|---|---|---|---|---|
| 0.5% | 0.5 gal. | 1.0 gal. | 1.5 gal. | 2.0 gal. |
| 0.67% | 0.67 gal. | 1.34 gal. | 2.0 gal. | — |
| 1.0% | 1.0 gal. | 2.0 gal. | — | — |
| 2.0% | 2.0 gal. | — | — | — |
Note: 1 gallon = 4 quarts = 8 pints = 128 fl. oz.
For Backpack Sprayers, Knapsack Sprayers, and Hand-pressurized Pump Sprayers.
| Gallons of Water | 1 | 2 | 3 |
|---|---|---|---|
| 0.5% | 4 teaspoons | 2.5 tablespoons | 2 fl. oz. |
| 0.67% | 5 teaspoons | 3.5 tablespoons | 2.5 fl. oz. |
| 1.0% | 2.5 tablespoons | 5 tablespoons | 4 fl. oz. |
| 2.0% | 5 tablespoons | 10 tablespoons | 8 fl. oz. |
Note: 1 fl. oz. = 2 tablespoons (Tbs.) = 6 teaspoons (tsp.)
Note: 1 gallon = 4 quarts = 8 pints = 128 fl. oz.
EPA Registration Number
For Trimec Classic, the EPA registration number is 2217-543, and for Trimec 992, it is 2217-656.
