My yard has seen an amazing turnaround in just the last year. The past 2
years I was complaining about almost 100% crabgrass coverage. I took it
very seriously, and now I can only find the occasional crabgrass plant. I
powerseeded in the fall, and was meticulous in my usage of pre-emergent
crabgrass preventer. The powerseeded grass came up thick and lush,
effectively choking up most crabgrass.

But I digress...

The one weed I had last year that seems to have come back is the one in the
following pictures...

http://www.bookac.com/Images/Lawn/weed1.jpg
http://www.bookac.com/Images/Lawn/weed2.jpg

This weed seems to grow in packs, in small sections of my front yard. It is
not deeply rooted, and is easy to pull. Can anyone identify it, so I can
treat it properly? It grows really high, about twice the rate of my grass,
so it sticks out after 4-5 days after mowing.