University of Maryland Extension

Weed of the Week - Crabgrass

Author: 
Chuck Schuster
Crabgrass

Crabgrass has been found germinating this Spring; Mark Schlossberg has found it in the Baltimore area. Understanding Crabgrass control is an important part of Spring weed control. Much effort is spent each year to control this Spring germinating weed, and in some cases the efforts do not yield the results that are desired. Understanding how these products work can help one determine if the failure is caused by timing or something else.

Products containing dithiopyr (Dimension), prodiamine (Barricade) and pendimethalin (Pre-M) are shoot and root development inhibitors. Using post emergent products that include Dithiopyr (Dimension), Tenacity (Mesotrione), Acclaim Extra (fenoxaprop-p-ethyl), Drive (Quinclorac), allow the use at a later date which in some cases is a big help. All of these products can be used on established turf, but not sites that will be seeded with new seed. Siduron (Tupersan) and Squareone (Carfentrazone - Quinclorac) are products that can be used in a turf setting when overseeding is considered. Timing of application; when soil temperatures reach 55-60 degrees Fahrenheit and there is available moisture to activate the process. It is important to remember that any soil disturbance after applicaiton will decrease the effectiveness as the barrier will be damaged. This includes aeration of the site. If aeration is desired, do it several weeks prior to the applicaiton of the herbicide.

Soil temperatures are in the proper range in some areas at this time. Moisture is available and rainfall has been timely but, be aware, that rain events that produce heavy downpours will decrease some of the positive desired results.

Maintained by the IET Department of the College of Agriculture and Natural Resources. © 2019. Web Accessibility