Fall applications of herbicides, such as 2, 4-D or combination products (Trimec, Weed-B-Gon, Weed-Out) that contain 2,4-D, MCPP and Dicamba, are effective because the chemicals will be moved to the roots along with the sugars. It is important for the plants to be actively growing for herbicides to work.
It is best to apply herbicides when the outdoor temperature is 50 degrees F or higher. Weed Free Zone (also sold under the name of Speed Zone) contains the three active ingredients mentioned above, plus carfentrazone. It will give a quicker response than the other products mentioned especially as the temperature drops below 50 degrees F.
Weed control begins with prevention. Maintaining a healthy, dense lawn and mulching planters in early summer reduces the need for herbicides later in the year. Once weeds have germinated applying mulch is not as useful for control. Hand pulling young weeds is practical for small areas before the roots become established. (Cynthia Domenghini)