Fall is a excellent time to control white clover, dandelion and many other perennial landscape weeds. While not true for all perennials, for many perennial weeds fall is a time when they are translocating much of the sugars produced from photosynthesis down to the root system. This increases herbicide translocation down to the root system, which is where you want the herbicide to go once it is taken up by the plant. As long as the plants are not water stressed or stressed in other ways, systemic herbicides applied at this time will get the maximum translocation to the root system, resulting in more effective results. For more information on weed control and assistance with weed identification, visit the eXtension site: Garden, Lawn, and Landscape Pests: Weeds.
