Broadleaf Weeds, Weed Grasses, and how to Control them, by Mark Govan, Host of “Florida Gardening” on 970WFLA Live on Sunday’s 7-9am.
Freezes, frosts, and lingering cool weather may have delayed our landscape plants from producing the blooms and foliage we normally see by now, but the weeds in our lawns and beds have been growing profusely. Now that our temperatures are beginning to normalize, it is time to remove these weeds from our landscape. In order to accomplish this, we must understand there are different types of weeds. Weeds can be divided into three separate groups. These groups are broad-leafed weeds, grassy weeds, and sedges. In this article, I will help you distinguish between these different groups of weeds, and I will also recommend controls to help you reclaim your property. Let’s get started.
Broadleaf weeds are weeds that look like weeds. They normally have a broad or wide leaf and a flower. An example of this would be the dandelion. Weed grasses are weeds that look like your grass, but no flowers. An example of a grassy weed would be Carpet grass, which is very common in St. Augustine Grasses. Sedges are weeds that also look like grass, but have a triangular stem and produce either a single nut or a group of nuts at the top of the stem. If you cannot identify the type of weeds you have, then send a photo to my e-mail address at firstname.lastname@example.org. Properly identifying your weed and applying the right control, will save you time, money, and effort.
Regardless of what type of weed I am treating for, I like to use liquid herbicides because I can place the product where the weeds are, and I do not have to treat the entire lawn. Selectively spraying just the areas of the lawn where weeds are present, saves time and money. Granular herbicides are effective, but you have to cover the entire lawn for them to be effective. I have also found that many granular products are labeled for southern lawns, but some of these products can actually kill or damage your turf grass. Again, I prefer to spot treat the areas of my lawn that have weeds.
When liquid herbicides are sprayed directly on a weed, you get quicker control because you can coat the entire weed. Another benefit to liquid herbicides is that you can mix up fresh product each time you need to apply it. A quick note to all homeowners, weed control means killing eighty to ninety percent of the weeds in your lawn. Do not try to kill every weed in your lawn. There is a half-a-ton of weed seeds for every acre of grass in the world. This means you will always have new weeds coming up. Because most of our lawns in Central Florida consist of St. Augustine grasses, I will start here.
To control broadleaf weeds in St. Augustine lawns, you will need to use an herbicide with the active ingredient “Atrazine” or a new product called Celsius. Celsius may cost much more than Atrazine and can be harder to find, but if you are looking for results, then you need this product. You will also need to purchase a Non-Ionic surfactant. Surfactants help herbicides adhere to the leaf of the weed, giving you better control. You should be able to find these herbicides and surfactants at most garden centers. Always read the label for proper mixing requirements. Only mix an amount you will use today. Do not leave any mixed product in your sprayer. You should skip mowing your lawn for several days so you have more leaf surface to treat. The longer the weed is when you spray it the better control you will see. Spray the weeds to the point of runoff. Do not water the grass for twenty-four hours after application for best results.
For broadleaf weed control in Bahia, Bermuda, or Zoysia grasses, I recommend you use a product called Trimec Classic. Trimec is a liquid herbicide that will control weeds in as little as seven to ten days after application. The addition of a surfactant is not necessary. The active ingredient in this product is 2-4 D and Dicamba. Most garden centers will carry several products that contain these active ingredients, so you do not have to find the brand name I mentioned above.
Weed grasses like wild Bermuda or Carpet grass have no post-emergent control. If you have these weed grasses actively growing in your lawn now, the only control we have is to kill them off with round-up and dig them out. After, you can re-sod the areas with new grass. New sod will help limit germination of weed seeds left behind by the old carpet grass.
Sedges can be controlled with a product called sedgehammer. Sedgehammer can be found at most garden centers. You will need to add a Non-Ionic surfactant to the mixture to get the best results. Do not over apply these products, read the label. Invest in a measuring device that you can use for your garden needs only. A baker’s measuring spoon set should suffice. Remember, most sedges in lawns thrive where water is applied regularly. To help in prolonged control of sedges, reduce watering.
If you treat your weeds just after the grass is cut, or if you mow your lawn following an application, then the effectiveness of the herbicide will diminish. The same holds true if you get a rainstorm, or if you irrigate your lawn directly after application. The length of time it takes for herbicides to work may vary, but do not be discouraged. Wait at least fifteen to twenty days, before making additional spot applications. Enjoy your landscape and remember, without plants, we would not be here.