Fountain grass foliage does not cut smoothly but shreds and the cut ends turn white. The shredded tips are highly visible on the right side of this photo.
Once in lawns Fountain grass can be difficult and costly to control.
Voight and Reicher found one or two spot treatments of glyphosate were very effective in killing Fountain grass in lawns but since this chemical also kills all other grasses this may not be a great choice especially for lawns with a heavy infestation of this weedy grass. In most cases reseeding would be required.
Products containing quinclorac would be a better choice as this chemical won’t kill bluegrass, tall fescue, ryegrass or zoysiagrass. (See the Drive 75DF label at http://www.cdms.net/LDat/ld4BF000.pdf for more detail). The problem with this chemical is it will most likely damage trees, shrubs and other ornamentals that have roots in the treated area.
Late Breaking News from Dr. Tony Koski, CSU Turfgrass Specialist - "Drive, when used to spot treat these clumps, will not pose a problem for trees. I've never seen ornamental injury caused by Drive, even when broadcast. Drive and quinclorac-containing products are the only effective selective options. Two applications of Drive XLR8 at full rate, about 10-14 days apart, provides good control. The homeowner RTU products (WeedbGon Maxx plus Crabgrass Killer, for example) will require more (maybe 3-4) sequential applications due to lower quinclorac concentrations. And definitely remove seedheads to prevent further problems."
If you decide to apply quinclorac it needs to be applied when the grass is in active growth as it is absorbed through the leaves and the roots. A 1.5 ounce bottle covers a 4000 square area. Online prices range from ~$17 to $40 for this size container so shop carefully. If you would prefer to have someone else do the treatment check with your local lawn care company or pesticide applicator for a quote!
To avoid the problem of Fountain grass invading your lawn avoid purchasing this grass.
A better option would be to select a Muhly grass such as Muhlenbergia capillaris as seen in the following photo. This is a native and hardy from zones 5 to 10. Some local nurseries should have Regal Mist or other cultivars of this colorful grass available in the spring.