Tenacity Herbicide - Questions & Answers

Tenacity is a systemic preemergence and postemergence herbicide for the selective contact and residual control of weeds in turfgrasses. When applied as a preemergent, weeds absorb Tenacity during emergence from the soil. Dry conditions following application may reduce the preemergence activity. If rainfall (0.15 inches) has not occurred within 10 days after a preemergence application, activate with 0.15 inches of irrigation. When used as a postemergent, susceptible weeds absorb Tenacity through foliar contact and soil absorption. Therefore, you should water in Tenacity when using it as a preemergent herbicide but it does not need to be watered in when using it as a postemergent herbicide.

You can mow your lawn 2 days before application of Tenacity Herbicide and 2-3 days after application. 

After spraying with Tenacity Herbicide, the foliage of treated weeds cease growth after application, then turn white (loss of chlorophyll), and death may take up to three weeks. A repeat application is required after two to three weeks for improved postemergence weed control. We would not recommend pulling up any weeds because the product will not get into the root system, and the weeds may come back at that point.

According to the Tenacity product label for smaller applications, you will need to mix 0.5 tsp of Tenacity and 1.5 tsp of surfactant to one gallon of water covering 1,000 sq ft.

You should keep the dogs off of the area while you are applying Tenacity and until the area has had a chance to dry, about 2-4 hours.

Tenacity Herbicide should not be applied to the lawn when temperatures are over 90 degrees or on day when you are expecting rainfall.

When the label states that no applications should be made when temperatures are above 80 degrees, this means that the product should not applied when it is 80 degrees and above. Tenacity Herbicide can be sprayed in the evening time and/or early morning hours.

 Tenacity Herbicide will be rainfast 4 hours after it has been applied or after it has dried. 

Tenacity herbicide is safe to use in a yard will pets will frequent as long as they are out of the area during the application. They can safely return after the area has dried.

Tenacity Herbicide can be used at the time of seeding or right after for most grass types. Fine fescue is the only grass seed that should not be used at the time of application. It is recommended that you wait 2-4 weeks after an application of Tenacity Herbicide to reseed with fine fescue.

The shelf life on most liquid herbicides all depends on how they are stored. If the product has been tightly sealed and kept out of sunlight and extreme temperatures, the shelf life is 3-5 years.

Yes, some folks do use food coloring to mark where  Tenacity Herbicide has been applied. 

Tenacity that has been mixed with water and a surfactant should be used within 24 hours of mixing and then discarded. If it is in its original container and stored away from extreme temperatures, it will have a three year shelf life unmixed.
 

When mentioning Tenacity Herbicide and temperature, we are referring to the temperature at time of application. If it gets above 70 degrees after your application has dried, that is okay. 

Yes, Tenacity is labled to control Ground Ivy "Creeping Charlie" as post emergent control. We highly recommend using a temporary turf colorant like Turf Mark Blue so that you can see where you spray with the Tenacity to avoid overlapping. Tenacity is a great product, but also a very strong product so too much overlapping or mixing the product too strong can cause temporary damage and whitening to your turf around the ground ivy. The color will come back in the lawn after 3-4 weeks but to avoid this potential problem it is best to use a colorant to make sure no overlap occurs. To get optimum results for post emergent control it is recommended you use a Non Ionic Surfactant in your mixture as well.

According to the Tenacity product label "Apply Tenacity at 5-8 fl. oz. per acre in at least 30 gallons of water per acre prior to seeding or post seeding of tolerant turfgrass species listed on this label, except fine fescue. Tenacity may reduce density of fine fescue seedings. Tenacity can be used on grass seed blends that contain less than 20% by weight of hard or fine fescue. Tenacity will control many monocot and dicot weeds that compete with and slow the establishment of the turfgrass stands. Apply at grass seeding or close to seeding for best performance. Avoid spraying on newly germinated turfgrass plants. Wait until the newly germinated turf has been mowed two times or four weeks after emergence (whichever is longer) before making a postemergence application." If you need more specific information on a turfgrass not mentioned on the product label you can reach the manufacturer at 866-796-4368.

The foliage of weeds treated with Tenacity cease growth after the application, then turn white (loss of chlorophyll), so death may take up to three weeks. A repeat application is required after two to three weeks for improved postemergence weed control.

Tenacity should not be applied with a hose end applicator. Tenacity if not applied evenly across the yard can temporarily whiten your lawn and cause you to not see full control of the weeds you want to eliminate. Also most hose end sprayers will not dial down to the small amounts needed per 1000 sq/ft that the Tenacity requires. Tenacity is best applied with some form of a pump/tank sprayer in even strokes without excess overlapping.

According to the Tenacity product label you will need to mix 1 tsp of product + 3 tsp surfactant with 2 gallon of water for spot treatments, using 1 gallon per 1000 sqft.

We contacted Syngenta which is the manufacturer of the product. According to Syngenta, once you have cut your grass, you would need to put the clipping in the compost pile and let it sit for at least 30 days. After 30 days the chemical has broken down in the clippings and can be used in other areas of the yard where you are growing garden plants.