Is this plant a friend or foe to my lawn?

I noticed a certain plant growing on my lawn this year that I haven't seen before. I took a couple of pictures. Can someone tell me if I have something to worry about. Right now they are growing in a spot where I find it tough to grow grass and they aren't really noticeable unless you look up close. I'm worried they might take over the entire lawn though. Here are the pics:
http://img206.imageshack.us/img206/5151/weedsdq4.jpg
http://img78.imageshack.us/img78/9940/weeds2ws6.jpg
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Joe said:

spot
entire
Looks like speedwell. You need to mow the lawn tall (to shade it out) and increase its thickness through proper fertilizing and watering. Speedwell (depending on species) is a winter annual or short-lived perennial, so a spring application of a pre-emergent is not going to control it.
Some people don't mind having wildflowers in the lawn, and speedwell has pretty (if tiny) flowers. So whether it's friend or foe is an aesthetic choice.
From NSCU:
" Establishing a dense, vigorous turf is the best way to reduce the encroachment of winter annual weeds. First, select adapted turfgrass cultivars for your area and then properly fertilize, mow and water to encourage dense growth. Watering scheduled to meet turfgrass needs helps to minimize chickweed competition.
"All of the winter annual weeds described, with the exception of corn speedwell, may be controlled with selective broadleaf postemergence herbicides if the desired turfgrass has tolerance. When controlling several different weeds, it may be desirable to select a combination product which is a mixture of two or three broadleaf herbicides. For corn speedwell, repeated application of a three-way combination product at one-half the label rate applied 10 days apart provides good control. ...
...
"The best time to apply herbicide to winter annual broadleaf weeds is from February through April--depending on the turf, location within the state, temperature and growing conditions. In warm-season turfgrasses, winter annual broadleaf weeds should be sprayed while the turf is still dormant and before spring green-up occurs. Spray before resumption of spring growth in cool-season turfgrasses. By spraying at these times, the turf has a greater chance of growing into those areas previously infested with weeds."
http://ipm.ncsu.edu/urban/cropsci/c08weeds/wintannu.html
--
Pat in Plymouth MI ('someplace.net' is comcast)

After enlightenment, the laundry.
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thanks, I have a hard time getting grass to grow in that area due to the exposed roots of a nearby tree. I really don't mind the plants and the flowers are pretty I just don't want them to take over my yard. I've fertilized and reseeded the yard already this year - paying particular attention to that area - and we've been getting lots of rain, so I'm not sure what else to do.
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on 5/29/2008 8:05 PM Joe said the following:

It's a friend in that it provides a green color if the grass is weak in that area. It's a foe in that grass won't grow stronger sharing the nutrients in the ground. Otho's Weed-Be-Gone, or similar, will kill it without hurting the grass, I don't know what it's called, but if it ain't grass, it's gone.
--

Bill
In Hamptonburgh, NY
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I like it in my yard. It grows well and gives green where nothing else will grow besides switch grass.YUK. I actually dug up a couple of plugs to plant in a shady area beneath some oak trees because I would rather have it there than all moss and mushrooms and switch grass. I don't use weed killers on my soil. These stay small and keep it green for longer through the year. When I want it contained in a particular area I use edging that goes about 3-5 inches into the soil because it spreads so well by roots. But if you are seeding and feeding your grasses it is not likely to take over. I like the variety it brings to the yard.
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