clethodim (Envoy and others)
Dahlia, daylily, and iris
Rate 0.1 to 0.25 lb ai/A
Time Apply to actively growing grasses.
Remarks Identify grasses and adjust rates for susceptibility, and stage of weed growth as label instructs. Add a nonionic surfactant containing at least 80% active ingredient at the rate of 1 pint/50 gal (0.25% v/v). Use of crop oil concentrate is not recommended as injury to flower and foliage may occur.
Caution Do not exceed 0.5 lb ai/A per season. Do not apply if rain is expected within 1 hour. Rotational grass crops such as corn and cereals may not be planted within 30 days of the last application. Grazing any plant product or residue is prohibited.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family Cyclohexanedione
clopyralid (Clean Slate)
Lily only
Rate Consult label
Time Apply as a broadcast application as an over-the-top broadcast foliar spray or as a directed spray from early spring to fall.
Remarks For spring planted bulbs, delay application until soil covering the newly planted bulbs has been settled by irrigation or rainfall. Multiple applications may be made as long as the total rate per growing season does not exceed 1.33 pints/A.
Site of action Group 4: synthetic auxin
Chemical family Pyridine
fenoxaprop (Acclaim Extra)
Daylily, iris, and peony
Rate 0.06 to 0.17 lb ai/A (13 to 39 fl oz/A)
Time Adjust rates depending on number of grass tillers (see label).
Remarks Ensure thorough coverage to actively growing, susceptible grasses. Repeat after grass begins active growth but do not exceed 120 fl oz/A per season.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family Aryloxyphenoxypropionate
fluazifop (Fusilade II)
Daylily, gladiolus, and iris (Idaho, Oregon, and Washington)
Narcissus (Washington only)
Rate 0.25 lb ai/A (16 fl oz/A)
Time Apply to actively growing grasses.
Remarks Narcissus listed on SLN label WA-130007. Identify grasses and adjust rates for susceptibility, and stage of weed growth as label instructs. Results often are erratic on grasses stressed from lack of vigor, drought, high temperature, or low fertility. More mature grasses and quackgrass can be controlled but may require two applications. Annual bluegrass and all fine fescues resist treatment.
Caution Do not exceed 32 oz/A per season. Do not apply if rain is expected within 1 hour. Rotational grass crops such as corn and cereals may not be planted within 60 days of the last application. Grazing any plant product or residue is prohibited.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family Aryloxyphenoxy propionate
pendimethalin (Pendulum Aquacap)
Crocus, daylily, lily, iris, narcissus, gladiolus, and tulip
Rate 2 to 3.9 lb ai/A (2.1 to 4.2 quarts/A)
Time Apply after bulb emergence, but before weeds germinate.
Remarks If weeds are present, product may be tank-mixed with a labeled postemergence herbicide. The product requires 0.5 inch of rainfall or irrigation to incorporate within 30 days of application. Use a lower rate on coarse soils low in organic matter.
Site of action Group 3: microtubule assembly inhibitor
Chemical family Dinitroaniline
sethoxydim (Segment)
Dahlia, daffodil, gladiolus, iris, and tulip
Rate 0.28 to 0.47 lb ai/A (2.25 to 3.75 pints/A)
Time Apply at optimum growth stage listed on label.
Remarks Identify susceptible grasses and add 2 pints/A nonphytotoxic crop oil concentrate to improve leaf absorption. Control often is erratic on grasses stunted or stressed from drought, high temperatures, or low fertility. Resistant grasses include annual bluegrass and all fine fescues, but quackgrass can be suppressed.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family Cyclohexanedione