We have been looking at recently sprigged pastures this past month to determine weed control needs. We can use Diuron immediately after sprigging, but for most everything else, the pasture needs to be established. So, when is it established?
There are a few ways to look at this. One way to look at it is, if you can pull on the plant and it snaps off – rather than pulling up roots and all – then it is “established.” There are other definitions of establishment based on runner length. Many of our herbicide labels answer this question. The label may say it is considered established when runners reach 8 – 10 inches. Sometimes labels describe establishment with days after sprigging and say, “use only on bermudagrass established for 60 days.”
The pasture pictured above has 8-10 inch runners in 40% of the pasture and the rest was 3 – 4 inch runners. In terms of safest postemergent application, UGA Extension Weed Scientist Dr. Patrick McCullough says, the 2,4-D and Weedmaster products will be the safest to use on immature bermudagrass during establishment. However, we are too risky to apply these products now, so mowing will be our only option here until we can buy some time on establishment.
Here is some TifQuik Bahia that was drilled in mid April. It’s only at 3/10 of an inch of rain since then, but coming up good. We have a more variety of weeds here, and automatically lose any option with mesulfuron since it’s Bahia. Some seedlings are still emerging, but most of it is 3 -4 inches. The rule of thumb here is when grass is 8 – 10 inches tall, it is considered established and safer to apply herbicides. In this situation, we would mow throughout the growing season, then come in the fall with a phenoxy herbicide to start control.