We don't recommend using Tenacity Herbicide to get rid of weeds in ornamental plants, it's not labeled for this use. If you have broadleaf weeds, you will need to spot treat with a non-selective herbicide. If you have grassy weeds, you can use a product like the Bonide Grass Beater around listed ornamentals on the label.
Foliage of treated weeds will cease growth after Tenacity Herbicide 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.
You would only need to water in the pre-emergent application of Tenacity Herbicide on dormant bermuda if you felt you did not use a sufficient amount of water during the initial application. Typically the goal is to create an even barrier in the soil with the chemical so the weeds cannot penetrate through it. Light watering no more than a 1/2 inch of rainfall equivalent is fine.
The product label for Tenacity Herbicide only states it is safe to be used on perennial ryegrass. There is no mention of it controlling Italian ryegrass, so I would not suggest using the product to control that particular weed.
Tenacity is usually pet safe as soon as it is dry. However, chickens are different and we would recommend reaching out to your vet for more information on what to do. Or you can reach out to the manufacturer for more information as well: Syngenta 866.796.4368.
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 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.
Whenever a lawn has large amounts of fine fescue its recommended to not use Tenacity unless some damage can be tolerated. Typically applying it as a pre emergent will lead to less harm than using it as a post emergent on a sensitive blend. We'd suggest applying the Tenacity as a pre emergent first, then wait 2-3 weeks to seed. Or seed and apply Tenacity 2 weeks after seeding.
Since a surfactant is designed to reduce water tension during spraying, applying it separately is unlikely to improve results. If you were applying the Tenacity as a pre-emergent herbicide, then there should not be any detriment to the application. If you were applying as a post-emergent, then you may need to reapply the product in 2-3 weeks as a spot treatment for the target weeds.
We would not recommend Tenacity Herbicide be applied to flower beds and ornamental plants. According to the product label: “Avoid over-spray or drift of spray applications onto ornamentals or flower beds and gardens. Roses and daylilies are sensitive plant species. Avoid applications over the top of exposed roots of trees and ornamentals."
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 Herbicide is one of the few products that can be applied at seeding, prior to seeding, or just after seeding of new grasses to help prevent and control weeds at the same time. Be sure to check the label for any restrictions to certain turf types as Fine Fescue is more sensitive than other species when using Tenacity at seeding. Be sure to use a Non Ionic Surfactant with the Tenacity when applying for best results.
Tenacity Herbicide is not labeled safe for use on Floratam species and is only for use on St Augustine grown for sod.
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.
Tenacity Herbicide, as well as any other herbicide, should not be applied to a lawn that is stressed due to drought conditions as you risk further damage being done to the lawn.
Tenacity Herbicide is only labeled to be used on Bermuda when it is fully dormant, otherwise it can be sensitive to applications and could harm it. It is not recommended for elimination of Bermuda or desired Bermuda turf.
We would recommend removing the dead bentgrass before planting your seed after using Tenacity Herbicide.
Tenacity Herbicide can last in the soil up to 30 days if used as a broadcast pre emergent treatment, so you would need to wait at least 30 days after an application before putting in any new seeds.
