OHP Marengo Herbicide

OHP Marengo Herbicide, manufactured by OHP, is a professional, selective pre-emergent herbicide liquid that delivers consistent, reliable control over germinating broadleaf and grassy weeds in production nurseries, hardscapes, and other ornamental production settings.

The active ingredient in this suspended concentrate is indaziflam, a highly effective compound from MOA Mode of Action Group 29. Indaziflam prevents weed seed germination by inhibiting cellulose biosynthesis, effectively stopping weeds at their earliest stage of development.

OHP Marengo Herbicide is an excellent selective pre-emergent herbicide that provides season-long control of both broadleaf and grassy weeds in ornamental production, nurseries, and specialty sites. For growers looking to save time, reduce labor, and maintain weed-free ornamental production areas, OHP Marengo Herbicide is an essential tool that delivers consistent, reliable results season after season.

Tools Needed

You will need a backpack sprayer or spray rig. 

How to Use

• Step 1: Determine how much OHP Marengo Herbicide to use by measuring the treatment area's square footage. Find the square footage by measuring the treatment area's length and width in feet, then multiply them together (length X width = square footage). For acreage, take the square footage and divide it by one acre (square footage / 43,560 sq. ft. = acres). For production ornamental uses, mix 7.5 to 15.5 fl. oz. of OHP Marengo Herbicide per 20 to 100 gallons of water per acre (which equals 0.17 to 0.36 fl. oz. of product in 0.5 to 2.3 gallons of water per 1,000 sq. ft.) as a broadcast or directed spray around ornamentals. For non-selective/hardscape use, apply 9 to 18.5 fl. oz. of product per 10 to 20 gallons of water per acre. For ornamental production facilities, mix 9 to 18.5 fl. oz. of product per 20 gallons of water per acre. Do not exceed 18.5 fl. oz. per acre of product for all applications within a 12-month period.
• Step 2: Fill the spray tank with half the amount of water, add the proper amount of product, and pour in the remaining half of the water. Close the tank lid and shake until well-mixed. It is stable in the spray tank for up to 48 hours after mixing. Re-agitate the spray solution before application.
• Step 3: The spray must be directed at the base of the plant or away from the plant. Do not allow OHP Marengo Herbicide to come in contact with the foliage, as some leaf malformations or discoloration may occur. For Christmas trees and conifers, direct the spray to the base of the trees with a band or with a broadcast application. Irrigate the treated area with 0.125 to 0.25 inches of rainfall or water after application. 

Where to Use

This product can be used in production nursery including inground and pot-in-pot container grown ornamentals, conifers and Christmas trees, non-bearing fruit and nut trees in nurseries, greenhouse floors (under benches), ornamental production facilities (such as shadehouses, hoophouses, and lathhouses) and hardscapes.

When to Use

Apply OHP Marengo Herbicide to dormant (prior to bud break) or actively growing plants. If the grower is uncertain about ornamental establishment after transplanting, wait 2 months before applying this product.

Safety Information

OHP Marengo Herbicide is safe to use around children and pets when applied according to the product label instructions. Always wear the proper personal protective equipment (PPE) when mixing and applying this product.

Keep people and pets out of the treated area until the spray has dried.

Special Considerations

Do not allow spray to contact foliage. OHP Marengo may cause localized injury to the foliage, especially young leaf tissue. If the spray should contact the foliage, remove affected foliage or wash off immediately.