Weed control applications usually cost around $100 each for a standard-size yard, and most professionals charge between $30 and $60 per hour for manual weed removal. Your total is affected most by the size of the weeded area. Some weed service companies offer weed control treatments, selective herbicide spraying, and manual removal and upkeep as part of a package, costing around $600 annually. You might pay less if you hire the same company for other lawn services, like flower bed upkeep, aeration, overseeding, and pesticide application.

Some of the particular herbicides that work best to get rid of nut grass without killing the grass include Halosulfuron-methyl, mesotrione, sulfentrazone, and metsulfuron. A herbicide like glyphosate would kill nutgrass, but it will kill nearby plants, too.

Due to its slow growth, Bahia grass does not generally take over weeds. In fact, the opposite can be true. Young Bahia grass is susceptible to being taken over by weeds. 

Likewise, in the cool season, Bahia grass goes into a dormant state that can allow weeds that thrive in early spring to get the upper hand. If you want to prevent weeds from taking over your yard, remove them by hand or apply a Bahia grass-friendly pre-emergent herbicide to your lawn before weeds have a chance to appear.

No, it's not really possible to completely prevent weed growth. Weeds are incredibly resilient—all they usually need is a tiny bit of dirt to sprout, so their eventual appearance is pretty much inevitable. However, you can definitely keep them at bay by getting rid of weeds as soon as you notice them. The longer you let them sit and grow roots, the more they'll spread.