Tenacity is not usually applied in December since it is most often applied to cool season turfgrasses, and it would be too cold in December to use herbicides in most areas with these turfgrasses. Whether Tenacity will work for your needs will depend on the type of desirable turfgrass you have and what specific weeds you are targeting. Tenacity is not safe to use on St. Augustine, zoysia, or Bermuda grass lawns.
Tenacity is usually applied as a pre-emergent in the fall or spring before overseeding with cool season grass such as rye or fescue. As a post-emergent, you would only spot treat with Tenacity as directed on the product label since this product can cause temporary whitening on desirable turfgrass.
Tenacity Herbicide cannot be used on residential St Augustine lawns and will not eliminate woodsorrel.
To control woodsorrel (also known as oxalis) in a St Augustine lawn, you could use a product like Hi Yield Atrazine, or Fertilome Weed Free Zone.
It is recommended to apply a pre emergent like Pendulum 2G in Fall and Spring. (55 degrees in the Spring / Between 70 and 55 degrees in the Fall). Pre emergents prevent weeds from germinating which will help cut down on the amount of post emergents needed during growing seasons.
View our St. Augustine Lawn Care Guide and Warm Season Calendar Schedule for more information.
Tenacity Herbicide can be applied as a pre-emergent before or at the same as seeding. We recommend that you only apply Tenacity after seeding if you can make the application within 7 days of seeding. Otherwise, you would need to wait until the new grass has come up and been mowed at least twice.
Tenacity Herbicide is only labeled to be used on Bermuda when it is dormant, otherwise it can be sensitive to applications and could harm it. Since Tenacity Herbicide can be used only on fully dormant Bermudagrass, there is not a time when you would be overseeding and using Tenacity at the same time. You would overseed with Bermuda when the turf is actively growing in spring or summer, if needed at all. So if you applied Tenacity on dormant Bermuda, then it would be long gone by the time the turf is completely green and any seeding would be done. If you would like to tell us more about the weeds you are targeting, then we can recommend alternate products for your needs.
Tenacity Herbicide should be applied on a non-windy day as directed on the label.
To control nimblewill, start applying Tenacity in the spring (late-April) with a nonionic surfactant. You will need to make two or three applications 2-3 weeks apart. You will use it at the 5 oz per acre rate per the label. The product does have a yearly maximum use rate, and the label states "do not apply more than 16 oz of Tenacity per acre per year or per crop (equivalent to a maximum of 0.50 lb of mesotrione per acre per year).You can also apply Tenacity in late summer and fall, but you should initiate them by August for best results. Good cultural practices on your lawn can help reduce its ability of coming back as well.
It would be best to wait to apply Tenacity Herbicide until the grass has completely dried before the application. Be sure to mix in a Non Ionic Surfactant when doing post emergent applications.
Tenacity Herbicide can be applied at the same time as seeding (unless grass is more than 20% stand of fine fescue). If application cannot be done within 7 days of seeding you would need to wait a minimum of 30 days, or until the seed has emerged and been mowed at least twice before applying to the lawn.
According to the Tenacity product label, you will need to mix 1 tsp of product + 3 tsp surfactant with 2 gallons of water for spot treatments applied at a rate of 1 gallon per 1,000 sq ft. It is advised to use a dye like Turf Mark Blue with it so you can make sure to not overlap if you plan to do a broadcast application on the property. Repeat applications can be done after two to three weeks for continued post emergent weed control.
Ideally, you would not want to put a fertilizer down when the lawn is getting ready to go dormant. If anything, an application could be made now in early October as your last treatment for the year. Tenacity would not be effective on lespedeza (japanese clover) at all as its not labeled for it. Southern Ag Atrazine is labeled for lespedeza and is safe for use on Centipede lawns if used as directed. Another option is Fertilome Weed Free Zone.
Tenacity Herbicide is not labeled for clump fescue, and it is safe for tall fescue.
You would want to wait 24 hours after the application of 1 product before applying the second product.
Tenacity is not labeled to be used on bahiagrass. The most effective product to control Nimblewill pre-emergently has been removed from the market (MSMA). We have had a lot of folks report that Dimension does a pretty good job pre-emergently but since the product is not technically labeled for Nimblewill we cannot legally recommend it for this use. The usual recommendation since the ban of MSMA is to use a non-selective product such as Round Up on the weed, wait 14 days and re-seed or sod the area.
Quackgrass is not on the label to be controlled by the Tenacity, and we cannot recommend you use it for your needs with it not being listed. We do however carry Certainty, which is a selective post emergent herbicide like Tenacity, and does have Quackgrass listed on the label for weeds controlled. You can see the dilutions and what grasses Certainty is safe to be used on, on the product label.
According to the Tenacity product label you can apply prior to seeding or post seeding of tolerant turfgrass species listed on the label, except fine fescue. If you are applying Tenacity after seeding, you should wait at least four weeks or two mowings, whichever is longer, before applying Tenacity.
Tenacity Herbicide is not labeled for post emergent control of burweed.
Tenacity Herbicide is only safe to use on dormant Bermudagrass, and it will not offer post-emergent control of poa annua, per the product label. A better choice to control existing poa annua in bermudagrass would be Monument 75WG Herbicide. Be sure to use a non-ionic surfactant with Monument as well. We also recommend using a pre-emergent herbicide such as Dimension 2EW or Prodiamine 65 WDG in late Summer/early Fall for the best control of annual bluegrass. Please see our Poa Annua Lawn Care Guide for more tips and information.
Avoid applications of Tenacity? over the top of exposed roots of trees and ornamentals. Please refer to the product label for full detailed usage instructions.
Tenacity Herbicide is not labeled to treat poa trivialis. Please provide your desired turfgrass for an alternate recommendation. Thank you!