You are right in the time of spring when control of broadleaf weeds is the most effective.

Before I go any further with chemical recommendations for broadleaf weed control, let me say this. The best way to control broadleaf weeds in the lawn is quite simple but will be surprising to many. You can cut down your dependency on pesticides, chemical weed control in this case, with a quality lawn. When you have a dense, dark green, tall, healthy stand of grass, it in itself is all you need to prevent those ugly weeds from poking their ugly heads through your lawn. Give a lawn with a thin stand of week grass that hasn’t been given proper management and those bare spots will encourage week growth. Stop and think, that’s why you have more moss and weeds under trees in your landscape. Back to chemical weed control if you need it. The use of a fertilizer impregnated with a broadleaf control chemical will work great.

Two cautions: make sure you don’t get the weed control under tender trees and shrubs. The second caution is that you can’t plant grass at the same time you attempt to use weed control. Best to control weeds now and plant grass in the late summer like mid September.