6 Best Herbicide For St Augustine Grass 2020 Buyer’s Guide

The Best Herbicide For St Augustine Grass. St. Augustine grass is a warm-season turf grass that has the characteristic of robust growth, tolerance to salt, cushy feel, and thick. To make it look green and healthy, St. Augustine grass has some high maintenance requirements. You have to keep the grass properly maintained. Especially to keep them from invasion of weeds.

To do this, there are variety of post emergence and pre emergence herbicides to control weed problems.

St Augustine grass is a native to coastal areas of the Mediterranean and Gulf of Mexico.

This grass produces broad, flat blades that form a thick mat. It spreads via above ground runners very fast. It is also easy to control if it grows in unwanted areas.

It is very tolerance to shade, but it needs at least four hours of sunshine per day. During winter, St. Augustine grass would be in the period of dormancy and turns brown.

In spring and warm temperatures, it greens up immediately. St. Augustine grass must be planted as sod, sprigs or plugs.

If you see the St Augustine grass is healthy, dense, actively growing lawn, it is a sign of good weed control, good watering and suitable fertilizing.

How to get rid of weed in St Augustine grass?

For weed control, like Crabgrass and other grassy weeds, you must apply pre-emergent herbicides.

This will control weeds before they sprout from the ground. The perfect time would be in the spring when soil temperature reaches 65 º Fahrenheit.

You can also apply post-emergent herbicides, that control weeds that have already sprouted.

You can apply these type of herbicides when weeds are already present or growing, and when the St Augustine grass is healthy and actively growing. It would be recommended to control weed when the weeds are still at its smallest growing stage.

Since St. Augustine grass is very sensitive to some herbicides, you must read the instruction label very carefully before applying any herbicide. You should know, how and when to use the herbicide product and how much to apply for your lawn.

What is the best herbicide for St Augustine grass?

Pre emergence herbicides safe for use on St. Augustine grass including Prodiamine, Isoxaben, Dithiopyr, Pendimethalin, Oryzalin, Benefin + Trifluralin, and Benefin + Oryzalin.

Post emergence weed killers safe for use on St. Augustine including Imazaquin, Halosulfuron, Bentazon, Atrazine, and 2,4-D + Dicamba + Mecoprop (MCPP).

Mixture of weed killers containing the pre emergence herbicide Isoxaben and the post emergence herbicides 2,4-D + Dicamba + Mecoprop (MCPP) are safe to use on St. Augustine grass.

List of best herbicide for St Augustine Grass

1. Quali-Pro Prodiamine 65 WDG (Generic Barricade 65 WDG)

Best Herbicide For St Augustine Grass

 This herbicide or weed killer is a broad spectrum pre-emergent herbicide product. Specifically for weed control including grass and broadleaf weed. You can apply this herbicide for the fall and spring. The product contains Prodiamine (65%). 

 The application of this product would be effective controlling Annual Bluegrass (Poa annua), Barnyardgrass, Carpetweed-04, Chickweed (common), Chickweed (mousear), Crabgrass (large and smooth), Crowfootgrass, Cup grass (woolly), Foxtails (annual), Goosegrass, Henbit, Itchgrass, Johnsongrass (seedling), Junglerice, Knotweed, Kochia, Lambsquarters (common), Lovegrass, Panicum (browntop, fall, and Texas), Pigweed, Purslane (common), Pusley (Florida), Rescuegrass, Shepherdspurse, Signalgrass Broadleaf, Speedwell (Persian), Sprangletop, Spurge (prostate), Witchgrass, Woodsorrel (yellow, from seed) and much more. 

This product is safe to be used on Bermuda grass, Bahia grass, Centipede grass, Kikuyu grass, Seashore Paspalum, St. Augustine grass, Tall Fescue (including turf-type), Fine Fescue, Zoysia grass, Buffalo grass, Kentucky Bluegrass, Perennial Ryegrass, Creeping Bentgrass, and other turfgrasses. This product does not leave a stain. It can be mixed along with fertilizer and iron solutions.

2. Snapshot Specialty Herbicide 2.5 TG – Active Ingredient Trifluralin + Isoxaben

Best Herbicide For St Augustine Grass

 This product is a selective pre emergent herbicide intended to control of numerous annual grasses and certain broadleaf weeds in St Augustine grass lawns, gardens, grass lawn, landscape, container grown ornamental, nursery stock, non bearing fruits, ground covers, tree plantations and other sites. 

 This product can give up to eight months of control without harming other plants. The recommended application would be 2.3 to 4.6 pounds per 1,000 square feet. It contains trifluralin, isoxaben and isomers. 

While applying this herbicide, you must wear coveralls, waterproof gloves, shoes and socks. There are many weeds it can control including spurge, jimsonweed, Signal grass, Knotweed, purple Coneflower, Milkweed, tall Morningglory and many more.

3. BASF Pendulum 2G Herbicide

Best Herbicide For St Augustine Grass

 This herbicide product can help your St Augustine grass lawn, sod areas or turf, by controlling most annual grasses and certain broadleaf weeds as they germinate but not the established weed. It contains an effective and active ingredient Pendimethalin. This ingredient will not be effective when used for an established weeds. For established weeds, it must be combined with other herbicide. 

 This product may also be not effective when used during cold weather, wet weather, hot and dry condition. Its efficacy will improve before 1/2 inch of rainfall or being watered within 30 days period. 

You must follow the instruction label during application for better result of weed control quality. Uneven or over application decrease weed control effects, stand loss, plant injury and soil residue. This herbicide can control and kill Crab grass, Foxtail, Evening Primrose, Hop Clover, Knotweed, Oxalis, Chickweed and many more.

4. XL-2G Herbicide

Best Herbicide For St Augustine Grass

 This product is a selective pre emergent herbicide. It contains benefin and oryzalin that can control certain annual grasses and broadleaf weeds. It can be used in St Augustine grass, Zoysia grass, landscape ornamental beds, turf grass, Bahia grass, Bermuda grass, Buffalo grass, Centipede grass, St. Augustine grass and Zoysia grass. 

 This granules herbicide only effective for weed as they germinate and not for established weeds. You must apply this product prior to germination of weeds or immediately after cultivation. Many factors can determine the length of weed control including weed population, potting media, soil conditions, temperature condition, watering, and few other factors. 

1/2 inches of rainfall or irrigation of 1/2 inch is recommended after this herbicide product application. Do not apply this herbicide on greenhouses, nuts, berries, fruits within 12 month of application, pots less than 4 inches wide, well rooted, and established ground cover.

5. The Andersons Pro Turf Barricade Granular Pre-Emergent Weed Control

Best Herbicide For St Augustine Grass

 This herbicide product contains Prodiamine (0.48%). It is good for pre emergence control of broadleaf weeds and grass in established turf grasses, St Augustine grass lawns and sod farms. This product prevents unwanted weeds like Crabgrass, Poa Annua, Goose grass, and henbit. The active ingredient is proven to kill those bad weeds that will not damage and harm your St Augustine grass plants. 

 It is recommended by the manufacturer to apply the product in the early spring and fall before weed seeds germinate. Activate the application with at least 0.5 inches of water during and within 14 days after the application. 

This would be suitable for St Augustine grass, Zoysia grass, Bermuda grass, Buffalo grass, Centipede grass, Kikuyu grass, Tall Fescue, Kentucky Blue grass, Fine Fescue and Creeping Bent grass.

6. Southern Ag – Surflan A.S. Pre Emergent Herbicide

Best Herbicide For St Augustine Grass

 This product is a selective pre-emergent herbicide for the control of numerous annual grasses and many varieties of broadleaf weeds. It can only control weeds growing from seed and not emerged weeds. It contains Oryzalin (40.4%). 

 When you are about to apply this herbicide, make sure areas to be treated should be free of emerged weeds. Weed residues, pruning, and trash should be removed before the application. 

This product can be used in established warm season turf including Bermuda grass, Bahia grass, Buffalo grass, Centipede grass, St. Augustine grass, Zoysia grass and Tall Fescue grass.

When is the best time to apply herbicide for St Augustine grass?

St. Augustine grass will grow at its best in the spring and summer months. It is when high temperatures are between 80 and 100 °F (37.78 °C). Plant St. Augustine grass at least 90 days before first frost, to give the grass enough time to develop.

It would be best not to apply weed killer during its first year of growth.

To avoid any damage to the St. Augustine grass, apply a post emergence herbicide before the grass at the greening-up stage and when grass starts growing.

Do not wait too long and while the grass has come out of dormancy. This could cause potential damage before applying a post emergence herbicide.

Before applying weed killer to St. Augustine grass, make sure the grass is not stressed from drought and water them if needed.

Apply a pre emergence weed killer in spring months, when temperatures are between 65 and 70 degrees Fahrenheit (21.11 °C) for four days in a row.

You can apply a pre-emergence weed killer in the fall months. You have to wait until nighttime temperatures reach 55 to 60 degrees Fahrenheit (15.56 °C) for four consecutive days.

How often to apply herbicide to St Augustine grass?

Herbicide may be applied during both dormant and growing seasons. The best results are commonly achieved when herbicide are applied in early spring or at the dormant period. The maximum number of time to apply herbicide are not more than two treatments per year.

Henry Kaswandi, SS, M.Kom.

I had been doing gardening for the last 18 years. I enjoy writing reviews of many products and about gardening to give better experiences and accurate information.