· Brooks Wilson's Answer
The best way to rid your lawn and landscape of this most bothersome weedy grass is by prevention. Weed and grass pre-emergents. To achieve true effectiveness Pre-emergents must be applied at specific times of the year and a specific program should be followed.
Post emergents are good for killing existing weeds, however, by preventing weeds you can eliminate, or drastically reduce the hassle of spraying or pulling weeds.
Here's some brief, but to the point, information on controlling weeds:
There are two kinds of pre-emergent. One for the lawn and one for your beds and island areas.
For The Lawn-
As mentioned above, to prevent weeds in the lawn, you should follow a Lawn Weed Prevention Program. Weed pre-emergents prevent seeds from germinating. There are several Lawn Fertilization and Weed Prevention programs here on Gardenality, or you can visit your local independent nursery to see what they recommend. The programs here on Gardenality have been tried and proven by Wilson Bros. Nursery in the state of Georgia. Depending on your location you may or may not be able to follow one of the Gardenality listed programs. These programs, however, will give you the basic guidelines of fertilization and weed prevention and can be printed and taken to your local nursery to find something comparable. It is highly recommended that you go to a independent nursery. They in general seem to have a lot more knowledge than do the big corporate stores. To find one of these Gardenality Lawn programs just type in the word 'lawn' in the search bar at the top of the page. Then on the drop down menu click on 'article'. Then hit the search button. Or you can click on the green colored Article Tab at the top of the page. Once at the Article section you can simply type in the word 'lawn' in that search bar. There are programs for Bermuda, Zoysia, Fescue, Bluegrass, Centipede, and St. Augustine grasses.
For Beds And Islands-
To prevent weeds and grassy weeds in flower beds and islands apply Treflan Granules just before the weed season. I apply it in early February. It only requires one application per year. Treflan can be applied over the top of any shrub, tree, ground cover, annual flowering plants, or perennial plants. The best product I know of is Hi Yield Weed and Grass Stopper. It comes in a 4 lb canister or a 15 lb bag if you have larger islands to cover. Treflan Granules prevent seeds from germinating.
To kill existing weeds and crabgrass in lawns the best product that I've found is Green Light Crabgrass Killer Plus -conatining Quinclorac, 2-4D, and Dicamba. Quinclorac is the ingredient that kills crabgrass. The other ingredients kill broad leaf weeds. It's in liquid form so you will need a measuring cup and a sprayer, or a more professional hose end sprayer. Read the label to make sure that you apply this product correctly.
For Beds And Islands-
To kill existing weeds in islands you can spray glyphosate. Glyphosate kills all plants, weeds, and grasses so you will need to selectively spray only the weeds. Hi Yield Killz All is a great product. Round-up also contains glyphoste, however, is usually a lot more expensive.
Here's a good article on weed control in islands and beds:www.gardenality.com/Articles/405/Problems-and-Solutions/Weeds-and-Invasive-Plants/How-To-Control-Weeds-In-Landscape-Beds/default.html
Hope this helps you out.