• Common lawn weeds like this dandelion can be difficult to get rid of.dandylion weed image by Lansera from Fotolia.com
  
  Anyone who cares for a lawn knows that eliminating weeds can be a struggle year after year. Weeds are undesirable because they use water and nutrients in the soil that should be going to the grass. They often grow faster than the grass, making the lawn look unkempt just a day or two after grooming it. Although lawn weeds vary by region, there are some that are typical in most areas where lawns are common.
  
  

Dandelions

• When a dandelion dies, its seeds are carried away on the breeze.dandelion image by Sorbotrol from Fotolia.com
  
  Dandelions may be a children's favorite, but for lawn caretakers, this weed is difficult to control. These small, yellow broadleaf weeds sprout up in the early spring and can continue to pop up in the lawn throughout the spring and summer. When a dandelion reaches the end of its life cycle, the head turns white and puffy. Each dandelion produces thousands of seeds that float easily on the breeze to establish themselves elsewhere.
  
  To control dandelions, lawn caretakers can use broadleaf weed killers as a spot treatment method. They should use caution, though, because the weed killer will not discriminate between weed and vegetable plant, for example. Pulling dandelions by hand is a non-chemical method, but the weed's root must be pulled entirely to stop it from growing back. This is best done in wet soil while the dandelion is still yellow.
  
  

Crabgrass

• Crabgrass is often used as a blanket term for some unwanted, grassy weed that shows up in the lawn each spring. But real crabgrass is a warm season weed that grows during the heat of the summer when the lawn grass offers less competition. Crabgrass grows along close to the ground with stems that extend outward like crab legs. It is typically lighter in color than the lawn grass. It grows in sunny areas only, and if it was present last year, it will almost certainly be present this year. Drought conditions often encourage crabgrass.
  
  The best way to control crabgrass is with thick, vigorously growing lawn grass. Thick grass will allow less sun to reach the crabgrass and choke it out. Grass should not be mowed too short, because this will also allow crabgrass to get the sun and space it needs. Pre-emergent or post-emergent herbicide applications will kill crabgrass, but should not be used while new lawn grass is growing.
  
  

White Clover

• White clovers are especially common in the northern United States.pure white flower of hop-clover image by alri from Fotolia.com
  
  White clover is a broadleaf weed that is most commonly found in the northern half of the United States. It first emerges in the spring. The leaf portion of the clover is easily recognizable, with three-part leaves, and in rare cases, four-part. The flower is white and spherical. Some lawn caretakers don't mind some clover in the lawn because it helps keep nitrogen in the soil, and can help give the lawn a greener, thicker look. Conversely, clover tends to die out easily during drought periods and in early fall, leaving brown patches in the lawn.
  
  To eliminate clover, lawn caretakers should spray a post-emergent herbicide in the fall.