My lawn is very healthy and happy, but all around the paved margins of the lawn crab grass is growing. The crab grass does not grow where the lawn abuts unpaved ground. For example, where there are mulched areas or wooded areas or forested areas, there is no crab grass. It is only where the grass meets asphalt or brick pavers in the walkway. The crab grass is much more prevalent along the asphalt than the brick walkway. Along the walkway there is only a crab grass plant here or there, but along the asphalt it is solid crabgrass.
The soil is marine clay (leda) and climate is New England coastal.
Why is crab grass growing in these margins and how can I get rid of it and get lawn right up to the asphalt?
Is the asphalt poisoning the lawn? Do I need to put some kind of buffer there like brick pavers along the asphalt?