Bulb and Flower Beds
Multiply rate by 0.023 for amount per 1,000 sq ft
BULB AND FLOWER BEDS—Preemergence, Soil-applied Treatments
dithiopyr (Dimension 2EW)
Iris, tulip and lily
Rate 0.375 to 0.5 lb ai/A (0.75 to 1 quarts/A)
Time Apply preemergence around bases of bulbs in landscape.
Remarks For best results, prepare a weed-free surface with minimal clods and leaf debris.
Caution Do not exceed 1.5 fl oz/1,000 sq ft every 3 to 4 months or 4.5 fl oz/1,000 sq ft per year. Do not apply to plant roots or weakened ornamental plants or when drift potential is moderate to high. Do not use in enclosed structures. Dithiopyr is toxic to fish and highly toxic to oysters, shrimp, and other aquatic organisms.
Site of action Group 3: microtubule assembly inhibitor
Chemical family Pyridine
EPTC (Eptam 7E)
Rate 5 to 14.9 lb ai/A (5.7 to 17 pints/A) depending on target weed species
Time Apply 2 weeks after transplanting herbaceous flowers in spring.
Remarks For annual weeds, incorporate to 3 inches deep, use lower rate, and incorporate with nursery cultivator or rototillers. For perennial weeds such as nutsedge and quackgrass, use higher rate and incorporate to 6 inches for suppression. Inhibits shoots of emerging seedlings.
Caution All flowering bulbs, salvia, phlox, snapdragon, and ornamental pepper are susceptible to EPTC.
Site of action Group 8: lipid synthesis inhibitor but not an ACCase inhibitor
Chemical family Thiocarbamate
isoxaben (Gallery 75DF)
Bulbous iris, daffodil, gladiolus, hyacinth, lily, and tulip
Rate 0.495 lb ai/A (0.66 lb/A)
Time Apply 2 to 4 weeks after planting, before bulbs and annual weeds emerge. Also may apply after bulbs emerge but before they flower.
Remarks Activate with 0.5 inch water or shallow cultivation before weeds emerge. Chemical stability remains adequate when left on soil surface for 21 days. Primarily for broadleaf control.
Caution Not for commercial production sites. Not recommended on tulips taller than 0.75 inch, or on gladiolus before emergence, or if corms were less than 1 inch in diameter, or on bulbs while they are flowering.
Site of action Group 21: inhibits cell wall synthesis Site B
Chemical family Benzamide
oryzalin (Surflan AS)
Bulbous iris, daffodil, hyacinth, and tulip
Rate 0.75 lb to 1.5 lb ai/A (0.75 to 1.5 quarts/A) depending on target species and time of year applied.
Time Apply 2 to 4 weeks after planting ornamental bulbs but before annual weeds emerge.
Remarks For fall-planted bulbs, apply in late winter to weed-free soil. Inhibits mitosis in roots and shoots.
Caution Do not apply to emerged tulips taller than 0.75 inch.
Site of action Group 3: microtubule assembly inhibitor
Chemical family Dinitroaniline
oryzalin + benefin (XL 2G)
Including bulbous iris, daffodil, hyacinth, and tulip
Rate Bulbs: use 75 to 150 lb/A depending on soil texture and time of year. Flowers: use 200 lb/A per application with at least 2 months between applications, not to exceed 800 lb/A per year.
Time Apply before target weeds germinate or immediately after cultivation. For bulbs, apply 2 to 4 weeks after planting but before weeds emerge.
Remarks Consult label for tolerant flowers and bulbs. (Inhibits cell division or mitosis, primarily in roots.)
Caution Do not apply to tulips emerged to 0.75 inch high or more, or to gladiolus before it emerges, or to plants less than 1 inch in diameter. Sensitive species include Douglas-fir, eastern hemlock, and begonia.
Site of action (both) Group 3: microtubule assembly inhibitor
Chemical family (both) dinitroaniline
oxadiazon (Ronstar 50 WSP)
Gladiolus only
Rate 2 to 4 lb ai/A (4 to 8 lb/A) depending on target weed species
Time Apply any time to weed-free soil and irrigate with 0.25 to 0.33 inch water immediately after applying for annual weed control.
Remarks Do not cover with soil or mulch, or incorporate, because weed control will desist. Weeds in the pink family (chickweed, mouseear chickweed, and pearlwort) are resistant. Primarily broadleaf control (controls weed seedlings by contact action during emergence.)
Caution See label for sensitive ornamentals, which include varieties of rhododendron, spruce, hemlock, azalea, viburnum, and cotoneaster. Avoid contaminating water intended for irrigation. Do not use on plants that will produce fruit within 1 year.
Site of action Group 14: protoporphyrinogen oxidase inhibitor
Chemical family Oxadiazole
pendimethalin (Pendulum 2G)
Rate 2 to 4 lb ai/A (100 to 200 lb/A) depending on desired length of weed control
Time Apply before, during, or after planting bulbs. Apply to seeded wildflowers after flower seedlings have emerged but before weed seeds germinate.
Remarks May be applied to control susceptible weeds (primarily grasses) in bulbs (including crocus, daffodil, gladiolus, and tulip) and established wildflowers (including black-eyed Susan, California poppy, coreopsis, and oxeye daisy) listed on the label. Primarily for grass control. Soil should be loose and free of all established weeds. Water within a few days to activate herbicide before weeds emerge. Inhibits mitosis in roots and shoots.
Caution Granules may stain stone, wood, or other porous surfaces.
Site of action Group 3: microtubule assembly inhibitor
Chemical family Dinitroaniline
prodiamine (Barricade 65 WG)
See label for listed bulbs and wildflowers
Rate 0.65 to 1.5 lb ai/A (1 to 2.3 lb/A) depending on length of control desired, and number of applications per year.
Time Apply before or after bulbs and wildflowers emerge, but before weeds and desirable flowers emerge.
Remarks Irrigate soon after treatment to wash herbicide onto the soil surface and to activate it within the top layer of soil. Do not exceed 2.3 lb/A.
Site of action Group 3: microtubule assembly inhibitor
Chemical family Dinitroaniline
S-metolachlor (Pennant Magnum)
Many bulbs and flowers, except daffodil
Rate 1.24 to 2.48 lb ai/A (1.3 to 2.6 pints/A) depending on soil type and organic matter
Time After transplanting
Remarks Apply after transplanting and when soil has firmed around plant. Irrigate shortly after planting to wash the herbicide from foliage and to activate the herbicide in the soil. Will not control emerged weeds. Existing weeds must be removed. Primarily targets grasses but controls some broadleaves and suppresses nutsedge. Inhibits seedling roots and/or shoots.
Caution Consult label for tolerant and approved species. Do not apply more than twice per year.
Site of action Group 15: inhibits very long chain fatty acid synthesis
Chemical family Chloroacetamide
BULB AND FLOWER BEDS—Post-emergence or Foliar-applied Treatments
clethodim (Envoy)
Rate Consult labels
Time Apply postemergence to actively growing annual or perennial grasses as listed on label.
Remarks Consider environment and growth conditions that affect leaf uptake (see label).
Caution Do not exceed 68 fl oz/A per season.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family Cyclohexanedione
fenoxaprop ethyl (Acclaim Extra)
Daylily and iris only
Rate 13 to 39 fl oz/A or 1,000 sq ft
Remarks Adjust rates depending on number of grass tillers (see label). Ensure thorough coverage to actively growing, susceptible grasses. Repeat after grass begins active growth but do not exceed 120 fl oz/A per season. Inhibits fatty acid production, cell membranes, and new growth.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family Aryloxyphenoxy propionate
fluazifop (Fusilade II)
Alyssum, marigold, petunia, geranium, iris, zinnia, and many others
Rate 0.25 to 0.375 lb ai/A (16 to 24 fl oz/A)
Time Apply to actively growing grasses or within 7 days after irrigation with 0.25% nonionic surfactant when susceptible grasses are in the labeled growth stage.
Remarks Check label for crops that can be injured by over-the-top applications. Identify grasses and adjust rates depending on 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. Inhibits fatty acid production, cell membranes, and new growth.
Caution Do not tank mix with other pesticides. Do not apply within 5 days of other pesticide treatments.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family Aryloxyphenoxy propionate
sethoxydim (Segment)
Chrysanthemum, coleus, gladiolus, impatiens, iris, marigold, snapdragon, petunia, zinnia, and others
Rate 0.28 to 0.47 lb ai/A (36 to 60 fl oz/A)
Time Apply at optimum growth stage listed on the label.
Remarks Identify susceptible grasses. 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. Inhibits fatty acid production, cell membranes, and new growth.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family Cyclohexanedione