There are several herbicide products available for broadleaved weed control in lawn grass. Most of these products contain 2,4-D and dicamba and are applied as a spray. There are also several “Weed and Feed” products sold as granular materials, which can be applied with a fertilizer spreader.
I, personally, prefer the spray materials. Most lawns do not have a severe and uniform weed problem over the entire lawn. With a spray mix you can walk over your lawn and “spot treat” the areas which have a weed infestation. This takes a little time, but you use much less chemical and apply it precisely to the problem areas. You also avoid the possibility of getting the weed killer into flower beds and shrubs at the edge of the lawn.
Every year I see several cases of over-eager gardeners who have managed to unintentionally apply 2,4-D to plants, causing them to produce deformed and distorted growth and, in a few situations, actually kill some of their landscape plantings.
If you are really set on using a “Weed and Feed” material, plan to leave a three-foot untreated buffer at the edge of the lawn along the flower beds.
No matter what you use – spray or granule – apply it when the grass is dry and when the air is calm. Both spray-drift and dust drift can result in serious damage to broadleaved flowers and shrubs at the borders of your lawn.
If you do not wish to use herbicides, hand digging is the only other option.