New— Now offered in a smaller 18oz container size!

Marengo® is a pre-emergent selective liquid herbicide that offers long-term residual control of both grassy and broadleaf weeds on ornamentals grown in production nurseries including those grown in-ground and in pot-in-pot containers. Marengo may also be used on conifers, Christmas trees and greenhouse floors. Marengo can be used in ornamental production sites and hardscapes and is labeled for use in shadehouses and hoophouses in areas covered by landscape fabric, rock or under benches.


With the new active ingredient indaziflam, Marengo offers unparalleled, season-long control of many hard-to-control broadleaf weeds such as bittercress, groundsel, oxalis, marestail, and spurge. Marengo also controls tough grassy weeds such as crabgrass, annual bluegrass, and annual sedge. Marengo also demonstrates early post-emergence activity against some weeds, including annual bluegrass, crabgrass, and oxalis.


A suspension concentrate (SC) formulation, Marengo contains the first active ingredient from MOA (Mode of Action) Group 29. The active ingredient prevents weed seed germination by inhibiting cellulose biosynthesis. Marengo does not move once applied to the soil and does not volatilize. Marengo should be applied as a broadcast spray over ground areas and as a directed spray for field grown ornamentals.


Marengo use rates range from 7.5 to 18.5 fl. oz. per acre depending on soil type and conditions. Marengo should be applied in a minimum of 10 gal. of water per acre (one quart of water per 1,000/sq. ft.). Marengo performs best when applied to bare ground or mixed with a post-emergent herbicide to eliminate existing weeds. If tank mixing with Roundup® or Finale®, mix Marengo in the tank thoroughly before adding Roundup or Finale. For best results, users should activate Marengo with a minimum of ¼ inch of water within 2 days of application.


Users should avoid applications when spray particles may be carried by air currents to areas where sensitive crops and plants are growing. Avoid spraying with winds in excess of 10 mph.


Fall applications have shown excellent weed control through the following spring season. The fall application will provide weed control into the spring season, a time when nurseries are busy with other duties and the fields are muddy..


Current state registrations

Marengo Herbicide

Labeled for use on:

Ornamentals in outdoor nurseries, shadehouses, hoophouses, greenhouse floors and on Christmas trees, and in conifer plantations.


Labeled plants:

Marengo has shown excellent plant tolerance on a wide variety of ornamentals. Please consult the label for a full list. If a cultivar is not listed on the label, users should treat several plants at the single maximum desired use rate and evaluate 1 to 2 months later for possible injury and acceptable tolerance.



½ gallon containers, 4 to a case; 18 fl. oz., 8 to a case



Do not apply over the top of ornamental plants. Do not allow spray to contact foliage. Do not disturb soil surface after application. Do not use Marengo on nursery seedbeds, on rooted cuttings, or on young plants in liners. See the label for additional restrictions and precautions.

  • EPA Registration Number432-1518-59807
  • Restricted Entry Interval (REI)12 hours
  • Chemical FamilyAlkylazines
  • MOA29
  • Active IngredientIndaziflam
  • Rate per acre (see label)7.5 - 15.0 fl. oz.
  • Maximum rate18.5 fl. oz. per acre/per year
  • ApplicationLiquid directed spray to ornamentals; broadcast spray over ground areas