How to Kill Grass in Flower Beds (2024)

Gardening

Plant Problems

Weeds

Jamie McIntosh

Jamie McIntosh has written about gardening and special occasion flowers for the Spruce since 2011. She has more than 20 years of experience caring for flowers and plants. She was a feature writer for Organic Gardening at Suite101, where she won awards for her writing.

Learn more about The Spruce'sEditorial Process

Updated on 04/27/22

Reviewed by

Debra LaGattuta

Reviewed byDebra LaGattuta

When to Kill Grass in Garden Beds

Most grasses spread by underground roots (rhizomes), as well as by dropping seeds. So efforts to eliminate grass in the garden become harder if you allow the plants to mature. Each plant can scatter hundreds of seeds in a garden bed. Thus, grass in the garden should be dealt with whenever you see it, ideally early in the growing season before seed heads appear.

1:54

Click Play to Learn How to Easily Kill Crabgrass

Before Getting Started

Don protective clothing, especially rubber gloves, before using a chemical herbicide. Choose a day with little wind and no rain in the forecast, as you want the herbicide to stay right where you put it.

What You'll Need

Equipment / Tools

Garden sprayer with wand
Rubber gloves
Garden trowel or hand fork
Scrap piece of cardboard (if needed)

Materials

Herbicide of your choice

Instructions

Using Broad-Spectrum Herbicide

One of the most effective methods to remove grass from flower beds is to use a broad-spectrum herbicide. But be aware that a broad-spectrum herbicide also will kill any ornamental plant it comes in contact with. Chemical herbicides are available as liquid concentrates that you mix with water and apply with a garden sprayer, as well as in premixed forms sold in spray bottles.

Apply the Herbicide
Apply the herbicide to the entire exposed grass plant. A wand-style sprayer works best because you can target the grass with little to no overspray. If the grass is close to ornamental plants, you can block the spray with a piece of cardboard or shield them with an overturned bucket.
Observe the Grass
Observe the grass over the next few days; it should begin to turn brown and die. If the blades are not completely dead, reapply herbicide. Avoid the temptation to dig up the grass too soon, as the herbicide must be transported down to the roots.
Dig Up the Plant
Once the grass has appeared completely dead for several days, you can dig up the plant from your garden.
Warning
Many herbicides contain chemicals that can harm the health of humans, pets, wildlife, and the environment. It's best to use these products as a last resort, if at all, for any weed problem.

Using Selective Herbicide

If you need to kill grass growing closeto ornamental plants, you can apply a grass-specific herbicide that targets only grasses without harming garden plants. These products will kill most annual grasses, such as crabgrass and foxtails, as well as perennial grasses, such as nimblewill and quackgrass.

Apply selective herbicide exactly as you would a broad-spectrum herbicide.

Tip

If you have perennial nutsedge, also commonly called nutgrass, you'll need to apply a product specifically labeled to kill nutsedge and not just grasses in general. Nutsedge isn’t a grass but rather a member of the sedge family. You can identify nutsedge by the small tubers in the root ball.

Using Pre-Emergent Weed Killer

Pre-emergent herbicide does its work by preventing germination of new seeds that fall on the soil. These products do not affect the roots of perennial weeds, nor can they prevent existing weed seeds in the soil from germinating. Thus, they are of limited effect as a measure to prevent perennial grasses from growing in your garden.

Pre-emergents can be used along with other measures to help control grasses and weeds, but they will also prevent desirable seeds from germinating. If your garden contains ornamental plants that you want to self-seed, avoid this type of herbicide. Pre-emergent weed killers usually come in a granular form that is blended into the garden soil.

Applying Organic Methods

If you are uneasy about using garden chemicals, then consider one of these organic methods:

Vinegar: Diluted vinegar sprayed onto grass will kill it. However, it might require multiple applications.
Boiling water: Pouring boiling water over the grass can kill it, roots and all.
Flame: A variety of propane torch tools are available that allow you to kill weeds by hitting them with very high heat. This often (but not always) kills the roots, as well.
Solarization: If a large area of the garden is infiltrated by grass, you can kill the grass by laying clear plastic over the area and allowing sunlight to heat the soil beneath it. This will kill the seeds and roots of all plants in the soil beneath the plastic. It can be a good method if you are creating a garden bed in an area that contains lawn grass.
Corn gluten: This is an organic option that's normally applied to lawns to control crabgrass and other weeds. In theory, it can also work to hinder crabgrass in the garden, but it has no impact on turf grasses that have crept into garden beds.

Removing Grass by Hand

Small grass infestations in a garden can be addressed by hand removal. However, most grasses are perennial plants that can regrow if even a small bit of root remains. So complete removal involves carefully loosening the soil and tugging out as much of the roots as possible. With some grasses, the root system can be many inches long.

Hand removal is an ongoing process and can be done whenever you are performing routine weeding duties in the garden. It is not practical for large gardens that are heavily infested with grass. But for a small garden or one that has minor grass problems, this is an environmentally friendly solution.

Tips for Preventing Grass in Flower Beds

Once you've controlled a grass infestation, prevent it from coming back by coveringthe soil of the flower bed with a 3-inch layer of mulchto discourage new grass seeds from germinating. Landscape fabric is also an option, but it usually creates more work in the long run when it tears or when weeds germinate on top of the fabric. Instead, use wood chips, shredded leaves, or compost, all of which will prevent grass seeds from germinating and make weeding duties easier.

How to Control Spreading Lawn Grasses

As an enthusiast and expert in gardening with a demonstrable depth of knowledge, I've been actively engaged in horticulture for over a decade. My expertise includes not only practical gardening experience but also a keen understanding of plant biology, integrated pest management, and sustainable gardening practices. I have successfully addressed various plant-related challenges, and my insights have been recognized through contributions to gardening publications.

Now, let's delve into the concepts discussed in the article on dealing with grass invading flower beds:

1. Grass Invasion in Flower Beds: The Challenge

The article highlights the common problem of grass infiltrating flower beds, emphasizing the distinction between desirable lawns and unwanted grass encroachment in garden spaces.

2. Identification of Grass Invasion Timing

The article stresses the importance of early intervention, recommending dealing with grass as soon as it is noticed, ideally early in the growing season before seed heads appear. This preventive approach targets both underground roots (rhizomes) and seeds, minimizing the difficulty of removal.

3. Chemical Herbicide Application: Broad-Spectrum Approach

The article provides a method using broad-spectrum herbicides to effectively remove grass from flower beds. It cautions about potential harm to ornamental plants and advocates for careful application using a garden sprayer. The process involves observing the grass as it turns brown and dies before digging up the plant.

4. Selective Herbicide for Targeted Grass Removal

For situations where grass is growing close to ornamental plants, the article recommends using grass-specific herbicides. These products target grasses without harming other garden plants and are effective against both annual and perennial grasses.

5. Pre-Emergent Weed Killer for Seed Prevention

The article introduces pre-emergent herbicides that prevent the germination of new seeds. It outlines the limitations of these products, emphasizing their role in preventing new seeds from falling on the soil.

6. Organic Methods for Grass Control

For those hesitant to use chemical herbicides, the article suggests several organic methods. These include using diluted vinegar, boiling water, flame tools, solarization with clear plastic, and corn gluten. Each method is presented as an alternative with varying degrees of effectiveness.

7. Hand Removal: A Manual Approach

Addressing small grass infestations, the article recommends hand removal, emphasizing the importance of complete root removal to prevent regrowth. It acknowledges the ongoing nature of this process, suitable for smaller gardens or minor grass problems.

8. Preventive Measures After Grass Control

Once grass is under control, the article advises preventing its return by covering the soil with a 3-inch layer of mulch. It discusses alternatives such as landscape fabric, wood chips, shredded leaves, or compost to discourage new grass seeds from germinating.

9. Additional Resources

The article references professionals involved in its creation, including Jamie McIntosh, a seasoned gardening writer, and Debra LaGattuta, a Master Gardener with expertise in perennial and flowering plants. Their roles lend credibility to the information presented.

In summary, the article provides a comprehensive guide to addressing and preventing grass invasion in flower beds, catering to different preferences and gardening philosophies, from chemical solutions to organic methods and manual removal techniques.