How to Pick a Good Weed Killer for St. Augustine Grass

St. Augustine lawns are very popular as the grass is generally hard-wearing and looks great. It’s a warm-season grass and wears relatively well.  Like all grasses, with no intervention, it’s prone to getting weeds.  A good weed killer can have your St. Augustine grass looking great in no time.  We’ll cover a few good options, as well as how to get the most out of your yard.

Luckily there are many products available that will kill weeds but won’t affect your St. Augustine grass. Regularly applying a herbicide can help to keep weeds under control. Let’s look at which weed killer to use on St. Augustine grass.

The Best Weed Killer for St. Augustine Grass

Many great products are available that will kill weeds in your St. Augustine lawn without affecting the grass. Here are our two options that’ll knock the weeds right out:

Southern Ag Amine 2,4-D WEED KILLER

Best Weed Killer for St. Augustine

Southern Ag Amine 2,4-D weed killer is great for use on large lawns or areas such as golf courses, fence lines, and pastures. It kills broadleaf weeds without killing St. Augustine grass or other varieties of grass.

This product is very easy to use; it comes in a container with a handle that can be easily carried. It also comes with an applicator nozzle that has a low pressure and allows you to spray the product over your lawn and achieve even coverage.

You’ll need to mix the solution with water in the correct ratios and should always follow the instructions on the label. One bottle Southern Ag Amine weed killer has excellent coverage and works well for killing broadleaf weeds such as plantain, clover, dandelions, and chickweed. It’s best not to use this weed killer on vegetable crops as it is toxic to humans.  Here’s more on how long it takes 2-4D to kill weeds.

  • Kills broadleaf weeds such as dandelions, chickweed, plantain, and clover.
  • Can be used on large lawns or areas such as pastures, golf courses, fence lines, ditches, cemeteries, parks, and school playing fields.
  • Safe for St. Augustine grass
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Roundup for Lawns 1 Ready to Use – All-in-One Weed Killer

Weed Killer for St. Augustine Lawn

Roundup for Lawns is a great all-purpose weed killer that can be used to kill broadleaf weeds growing in St. Augustine grass. It comes with an extended wand that makes it very straightforward to spot-treat weeds. This product can be used to kill a wide variety of common weeds, including crabgrass, nutsedge, dandelion, and clover, without harming your lawn.

Roundup can be used on various grass types, including Kentucky bluegrass, fescue, Bermuda, Ryegrass, and buffalograss. The product is fast-acting and will begin to affect weeds immediately. It also becomes rainproof in just three hours. Crossbow is also a viable option. Here’s our guide to Crossbow vs. Roundup.

  • It can be used to kill 250 common weed species
  • Doesn’t harm grass, suitable for use on St. Augustine lawns.
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How to Kill St. Augustine Grass: Weed Killer for St. Augustine Grass

Weed Killer for St. Augustine

The other problem that homeowners have is that they are growing a different variety of grass, and St. Augustine grass has started to invade their lawn. While some people don’t mind the presence of St. Augustine grass on their lawns, others want to get rid of it. St. Augustine grass can spread horizontally, so it’s best to pull out the grass or apply herbicide before it invades your lawn.

St. Augustine grass can be challenging to remove by hand as it can be tricky to hold onto. It’s probably best to choose a good quality product to get rid of the St. Augustine grass as a general weedkiller won’t be very effective.

St. Augustine Care Guides

St. Augustine sod

Here are some articles that can help you grow the best St. Augustine lawn possible after using a weed killer.

  • How to Revive St Augustine Grass– St. Augustine is a warm-season grass, but even it doesn’t like being planted when it is scorching hot outside. This article will help you recover your grass if it is dying.
  • Bermuda Vs. St. Augustine– Both of these warm-season grasses do great but have their strengths and weaknesses. If you are having trouble getting St. Augustine started, you may want to check Bermuda out instead.  While it may have different strengths and weaknesses, you can use the same weed killer for Bermuda.
  • What’s Causing Green Patches in St. Augustine Grass?– Dark green patches are common in St. Augustine.  This article tackles how to get them out of there.


If you have a St. Augustine grass lawn and want to get rid of broadleaf weeds the above products will help. Controlling weeds isn’t a problem as long as you choose the correct product. You can treat your lawn without damaging the grass.

Before you purchase a product, always read the instructions to find out exactly what it should be used for. Some products are designed to kill St. Augustine grass in other lawns, while others will kill broadleaf weeds without affecting St. Augustine grass.


Last update on 2024-05-23 / Affiliate links / Images from Amazon Product Advertising API