Tenacity is not labeled to control undesirable ornamental plants, although it may harm them if sprayed accidentally. You will need to remove physically all the parts of the iris - including the rhizomes in the soil – in order to prevent these plants from regrowing the following year. You can use a glyphosate product such as RoundUp QuikPro to kill the above ground plants, but you will need to remove the rhizomes after spraying. This article has easy-to-follow directions on this treatment, which is best done in the fall.
Due to the strength of Tenacity, and the need to not over apply or overlap with it during application to avoid discoloring or excess stress to the desirable turf grass, we do not recommend mixing other post emergent herbicides in the same tank with it unless stated on the label. Tenacity should be applied with a Non Ionic Surfactant and a temporary marking dye like Turf Mark Blue to ensure no overlapping occurs to cause your turf to whiten. We would recommend applying the Triad Select in a separate application. Should you decide to try tank mix the two, we recommend doing a tank mix test first for compatibility, and test a small area to ensure safety to the lawn. Though be aware Tenacity is not labeled to effect bermuda at all.
Tenacity Herbicide only states that it can cause undesired injury to kikuyugrass but it does not give instructions on how to control with Tenacity, which leads us to believe it may only temporarily damage it rather than actually kill it all the way out. Once your new seed has come up and become established to tolerate herbicide use, you could use Hi Yield Turflon Ester to spray over the kikuyugrass to eliminate it from the ryegrass in the lawn.
Per the Hi Yield Turflon Ester Product Label for Control of Kikuyugrass:
Apply Hi-Yield Triclopyr Ester at a rate of 3/8 to 3/4 fluid ounces per 1000 square feet. To improve activity, MSMA herbicide may be tank mixed with the ½ quart per acre rate of Hi-Yield Triclopyr Ester. Three to four additional applications at 4 to 6 week intervals may be required to achieve control of kikuyugrass
If you are applying it as a post-emergent herbicide, then Tenacity Herbicide should be applied when there is no rain in the forecast for 24 hours. If you are using it as a pre-emergent, then it would need to be watered in and could be applied before rain as long as there is not so much rain that the application would just get washed away.
If you are applying Tenacity Herbicide for a crabgrass pre-emergent, then you would apply in late early spring before soil temperatures reach about 55 degrees. Keep in mind that if you are not overseeding in the spring, you usually want to use a different pre-emergent with longer soil residual or add another one for longer and more complete weed prevention.
We have more information in our Crabgrass Pre-Emergent Guide here.
If you notice on Tenacity Herbicide’s product label, there are two different rates for application. There is a broadcast rate- meaning spraying the entire surface of the property, and a spot treatment rate. Spot treatments are often a different use application than for broadcast, especially for a unique product such as Tenacity. The main broadcast applications being made are going to be used as a pre emergent. The broadcast applications are not best for post emergent control, and the manufacturer recommends spot treating when going after existing weeds. Controlling an existing weed and preventing weeds from seed germination will be two different application rates, and one uses a surfactant during treatment (post emergent) and one does not (pre emergent).
Also, you would only be calculating per gallon of water if you are doing a post emergent spot treatment. Pre emergent applications will have varying water volumes based on a customers turf type, density, application equipment, and application speed. This means you are focusing on an amount of chemical per square footage/acreage, and not per gallon. The water is merely the carrier to get the small amount of chemical distributed evenly across the correct amount of space to yield the intended results from the product. For many, a pre emergent application will vary from 1 gallon to 3 gallons of water per 1000 sq/ft.
If you do not know how much water you will cover 1000 sq/ft or an acre with, you can calibrate your equipment by using only water first, and mark off a 1000 sq/ft section of yard. Walk as if you are applying it with chemical in a way that seems like sufficient coverage for your lawns needs. When finished, look to see how many gallons of solution you used, and then you can move forward with determining how you need to mix it based on this information for your 4 gallon tank.
You should not mow within 2 days before or after an application of Tenacity Herbicide or any other herbicides.
Yes, the whitening of the target weeds and sometimes the turfgrass is normal per the manufacturer. Tenacity Herbicide is labeled to be used on Kentucky Bluegrass, Centipedegrass, Buffalograss, Tall Fescue, Perennial Ryegrass, & Fine Fescue. It is not labeled for Bermudagrass or Centipede lawns and can cause turf injury. The whitening you see is the active ingredient working its way into the weeds/grass which causes the loss of chlorophyll followed by the weeds dying off within 1-3 weeks..If using on cool season turf, you can reseed those damaged areas if needed.
Tenacity Herbicide is applied at 5oz to 8oz per acre (depending on the turf type) or for spot treatments, 2 tsp + 3 tsp Non Ionic Surfactant per gallon of water per 1,000 sq ft. Please refer to the product label for the mix rate and turf type you have.
Per the manufacturer, the 18 month waiting period after an application of Tenacity Herbicide applies to food crops but there are some trees that can be sensitive as well. Digging a hole where Tenacity was applied should not have much active ingredient residue, especially if the sod/grass is removed to plant the tree. Waiting 3-6 months after application would be acceptable.
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.
Tenacity Herbicide is not labeled for use on pasture land, and a 90 day waiting period is required after an application until it is safe to allow animals to graze on treated areas.
When using Tenacity, 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.
When using Tenacity Herbicide as a post-emergent, you can apply anytime before seeding, but keep in mind that it may take a couple weeks to kill the target plants, so you would want to wait for those plants to die before aerating and reseeding. It is recommended to rake out the dead plant matter prior to aerating and reseeding the lawn.
Tenacity Herbicide will kill the crabgrass, weeds, and clover eventually. However, if you are seeding you may want to remove the dead weeds to allow the seeds more room to grow. Otherwise, you can just leave it as is.
Battleship III is only for controlling broadleaf weeds and will not effect crabgrass or other grassy weeds at all. The label does not mention tank mixing with herbicides like Tenacity only fertilizers so we would not recommend doing so.
Tenacity Herbicide is labeled for post emergent control of actively growing lawn burweed (spurweed, stickerweed, sandbur, sanbur, and sandspur) but will not offer any pre emergent control to prevent sandbur from germinating. When using Tenacity for post emergent control of weeds, a Non Ionic Surfactant is needed.
View the full list of Weeds Controlled (Pre & Post Emergent) on page 9 of the product label.
If Tenacity Herbicide or any herbicide is exposed to extreme freezing or heat temperatures, the concentrate can and would lose efficacy. When stored in cool dry and temperature controlled environments, the shelf life is 3-5 years.
Yes, Tenacity Herbicide can be shipped to Minnesota. This product is only restricted to ship to Alaska and Puerto Rico.
When using Tenacity Herbicide as a pre-emergent and seeding, you can apply Tenacity before or at the time of seeding for best results as long as you are planting a turfgrass that is listed as tolerant on the product label (Kentucky bluegrass and tall fescue are tolerant). The key time to avoid spraying Tenacity on new seedings, either as a pre-emergent or a post-emergent, would be when the new seedlings have started to come up but are not yet established. Once you see new seedlings, you would want to wait at least four weeks or until the new grass has been mowed twice, whichever is longer.
Please refer to page 12 of the product label for complete application instructions around seeding.
When using Tenacity Herbicide as a post emergent application you are only spot treating the weeds directly per the product label not broadcasting across the entire lawn like you would when applying as a pre-emergent. It is recommended to apply when no rain is expected within 24 hours if treating active weeds so it has enough time to dry and be absorbed by the weeds. For pre-emergent applications you need to water it in so it gets down in the soil to create the barrier.
