Destroying Those Annoying Dandelions
Dandelions are such a common weed in lawns and in parks, it's hard to imagine that they are not native to North America. Dandelions were intentionally introduced to the Americas from Europe, where they were considered a beneficial plant due to their nutritional and medicinal value.
The name of the plant comes not from its golden mane, but rather from the serrated leaves of the weed, which form an outline like lion's teeth (thus the name "dent de lion", or teeth of the lion).
Dandelion seeds can be blown into your yard from miles away, so it is virtually impossible to prevent new plants from popping up periodically, especially if your neighbors are less than diligent in their own lawn maintenance.
If your lawn is mostly weed-free and you see a new dandelion plant sprout up, pull the whole plant, including all the roots, out as soon as possible. Do not let it go to seed.
You'll need to check on the area for the next few weeks to ensure you got all the roots. A new dandelion plant can be regenerated from less than one inch of remaining root, so complete removal and subsequent checking is important.
If your lawn is very large, or contains a very large number of dandelion infestations, you may wish to resort to herbicides. Common herbicides in use in various parts of North America are glyphosate (i.e. Roundup