Landscape weed control requires a three-pronged approach: prevention, cultural and chemical control. 

Weeds are opportunists.  If there is an area in the yard with little or no vegetation, or if the vegetation is highly stressed, weeds will flourish.  Their adaptability to difficult growing conditions is what makes us call them a weed.

Prevent weeds by encouraging the rapid establishment of ornamental plants or a dense, healthy lawn.  Keep large areas of your yard free of weeds through the use of weed barriers and mulch. 

Another basic is to identify the types of weeds present in your landscape.  Is the weed an annual, biennial, or perennial?

Annuals may be summer annuals such as crabgrass.  There are also winter annuals that germinate in fall and live over the winter, such as blue mustard.  Biennials like common burdock, houndstongue, and musk thistle require two seasons to complete their growth cycle.  Perennials that grow every year are common dandelion, Canada thistle, and field bindweed. 

With this prevention and identification knowledge, you are well on your way to getting landscape weed problems in hand.