Broadleaf Signalgrass Control: How To Get Rid of Broadleaf Signalgrass

This page is a general DIY guide for controlling broadleaf signalgrass. Using the products and methods suggested you get control of broadleaf signalgrass. Follow this DIY article and use the recommended products, and we guarantee 100% control of broadleaf signalgrass.

Broadleaf signalgrass is a summer annual grassy weed that appears similar to large crabgrass, but is a problematic weed species of its own. 

This weed is primarily a problem in agricultural areas, especially where corn is being grown and can significantly reduce yields. On a residential lawn, broadleaf signalgrass tends to spread very quickly and can overtake a lawn with their presence.

If you want to remove broadleaf signalgrass from your property, our easy DIY treatment guide will show you exactly how to eliminate this grassy weed permanently. Follow the step-by-step instructions below using the recommended herbicides to the right and you will be successful in removing broadleaf signalgrass for good.

Identification

Before proceeding with a treatment program, you will need to be certain that you are dealing with a broadleaf signalgrass infestation. Careless identification can lead you to using the wrong treatment methods which can be a waste of time and money. Below are the following characteristics to know what broadleaf signalgrass looks like.

• Broadleaf signalgrass is a grassy weed that reaches up to 3 feet in height. Leaves are short and wide with a distinct midvein in the middle of them. They are also smooth on both surfaces of the leaves and are often folded or creased near the tip.
• During this weeds seedling stage it's grass blades will appear maroon-tinged in color and resemble signal flags. As broadleaf signalgrass matures it will become semi-prostrate to the ground with the tips ascending upwards. Each seedhead has two to six branches that are generally flat in appearance and measure 1 to 3 1/2 inches long.  
• Broadleaf signalgrass is often confused with crabgrass, but it can be differentiated by the hairs on its leaves. Crabgrass will be hairy on the upper leaf surface whereas broadleaf signalgrass will not have any hairs except at the margins and collars. 

Use the above description and image provided to help you identify broadleaf signalgrass on your lawn. When you're unsure or can't quite pinpoint exactly which kind of weed you are encountering in your yard, turn to the experts to ID the weed for you.

Inspection

Once confirmed that you are dealing with broadleaf signalgrass, you can then move on to inspection. During this phase, you will locate areas where broadleaf signalgrass is thriving and observe the conditions that are allowing it to thrive. This information will help you in knowing where to focus your herbicide application.

Where to Inspect

Broadleaf signalgrass is commonly found in Tennessee, but can also be located throughout the southeastern half of the United States. 

Commonly this weed is found in disturbed, open, and sandy sites such as crop and agricultural fields, ditches, and along roadsides. 

What To Look For

The short and broadl leaves of Broadleaf signalgrass will make it easily stand out among turf and other areas. Younger broadleaf signalgrass blades will have a maroon tinge on the blades.

Treatment

When handling any type of herbicide, you are properly protecting your skin and eyes with safety equipment (Goggles, gloves and long-sleeved clothing)

To get rid of broadleaf signalgrass in lawns, we recommend using a post-emergent herbicide such as Quinclorac 1.5 L. Be sure to read the label to determine if you turf type is tolerable to this product. 

Step 1: Mix and Apply Quinclorac 1.5 L 

Quinclorac 1.5 L is a effective post-emergent herbicide that ensures fast control over broadleaf and grassy weeds such as broadleaf signalgrass in residential lawns and other terrains. 

Determine how much Quinclorac 1.5 L to use by measuring the square footage of the treatment area. To do this, measure the length and width of the treatment area in feet then multiply them together (length X width = square footage). 

To control broadleaf signalgrass in turf as a spot treatment, use 1.45 fl. Oz. of Quinclorac 1.5 L per 0.5 gallons of water per 1,000 sq. ft.

Mix and apply this product with a backpack sprayer or handheld pump sprayer. 

Add half of the appropriate amount of water, then fill with the measured amount of Quinclorac 1.5 L. Lastly, add in the remaining half of water. Secure the lid and agitate until evenly mixed together.

Step 2: Reapply if Needed

Adjust your sprayer nozzle to a fan tip setting, then spray the top and bottom of broadleaf signalgrass leaves until evenly coated. Do not spray to the point of runoff.  

Under certain conditions, application of Quinclorac 1.5 L made to annual grasses at 2 to
4 tiller may not provide complete control. A sequential application will be required for grass
control in these situations. 

Do not apply to Bahiagrass, carpetgrass, St. Augustinegrass, centipedegrass, dichondra, or
lawns or turf where desirable clovers are present.

Prevention

Once broadleaf signalgrass has been eliminated from your property, you will need to implement some preventative measures which will ensure that this weed does not return.

• Broadleaf signalgrass will take a bit of persistence in order to completely get rid of it but if you do manage to be successful in removing it, you don't want it to return. Prevent broadleaf signalgrass from growing with the help of a pre-emergent like Barricade Pre-Emergent Herbicide Prodiamine Granular. Depending on your turf grass species, you will want to apply 1.5 to 4 pounds of product per 1,000 square feet. After application, water in the product with at least half an inch of water.
• This weed is very competitive in growth so we recommend regular fertilizer and standard lawn cultural methods. This can be from mowing when turf reaches a height of 3 inches, adjusting irrigation to no more than 1 inch once per week, and adjusting crop fields to have more narrow rows for less weed growth. 

Key Takeaways

What is Broadleaf Signalgrass

• Broadleaf signalgrass is a summer annual grass which grows vigorously from May to October.

How to Get Rid of Broadleaf Signalgrass

• We recommend using either a post-emergent herbicide such as Quinclorac 1.5 L to remove broadleaf signalgrass. 

Preventing Broadleaf Signalgrass Reinfestations

• Prevent the reappearance of broadleaf signalgrass by applying Barricade Pre-Emergent Herbicide Prodiamine Granular in the fall and maintenance practices  that promote a healthy, nutrient-rich turf that will make it hard for the weed to establish.