Start By Identifying the Weed
The best way to have your weed(s) identified is to take fresh samples (sealed in a plastic bag) to your local nursery and garden center.
The simple definition of a weed is a plant that's not wanted, or at least not wanted where it's growing. Weeds are plants that are well-suited to the local climate and growing conditions, which makes them prolific and resilient.
How you eliminate or control the weed depends on whether it's an annual, biennial, or perennial. Annual weeds complete their growth in a single season and have shallow roots. Annual weeds should be destroyed before they flower and make seeds. Perennial weeds are harder to remove since they may have large taproots, rhizomes, or runners that are hard to get rid of completely. The tiniest piece of root remaining after pulling a perennial weed can produce a new plant.
Weed Alert is a website that has a massive listing of weeds broken down into regions. They have a weed database that allows you to first identify a weed from a thumbnail photograph. Problem is, there are thousands of types and varieties of weeds! But if you have some extra time on your hands and want to learn more about and identify the weeds growing in your landscape visit WeedAlert.com
Methods of Weed Control in a Fescue or Bluegrass Lawn
Preemergent Weed Control
If you DO NOT intend to overseed your Fescue or Bluegrass lawn in Spring, apply a granular weed preventer in late winter to prevent the emergence of spring weeds such as crabgrass. A mid to late spring application of a weed preventer can also be beneficial for prolonged control of summer weeds.
Post Emergent Weed Control
To kill existing weeds that have already emerged in your Fescue or Bluegrass lawn, apply a postemergence herbicide that is labeled for use on Fescue or Bluegrass lawns. There are many types and brands of post-emergent herbicides. Take a sample of your weeds to your local nursery and garden center for identification and to get recommendations on what type of chemical to use. Apply postemergence herbicides only when weeds are present. Always be careful to follow mixing and applications instructions on product label. Spot treating is always recommended.