11 Best Weed Killers For Flower Beds And FAQ

There are several different kinds of weed killers available on the market today.

To decide which weed killer is suitable for your garden, it is important to understand what kind of weeds you need to eliminate.

Most weed killers work on many weeds, but stubborn weeds like crabgrass may need a more potent formula.

When using a weed killer in a flower bed, it is crucial to ensure the formula is safe to use without causing harm to your flowers.

You also need to consider how many weeds you have to determine the proper course of treatment.

For just a few weeds in your flower bed, a very basic, one-time treatment may be used to eliminate them.

If your flower bed has a large number of weeds, or if the weeds are a stubborn variety, a more intense treatment will need to be used.

An overgrown flower bed may even require multiple treatments before the weeds are completely eradicated.

Keep reading for a list of the 11 best weed killers for flower beds, as well as answers to a few commonly asked questions about weed control.

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Green Gobbler Vinegar Weed & Grass Killer

Green Gobbler Vinegar Weed & Grass Killer is a non-selective herbicide formulated with 20% vinegar.

This herbicide is safe to use in flower beds and is excellent at killing broadleaf weeds and grasses such as: 

  • Clover
  • Crabgrass 
  • Chickweed 
  • Moss

This product is also easy to apply with the included trigger sprayer, although it could easily be poured into a pump sprayer if you prefer.

Green Gobbler Vinegar Weed & Grass Killer may be used straight from the bottle, requiring no mixing or dilution.

The herbicide has been formulated to kill weeds within hours, and it does not contain any dyes or harsh chemicals such as glyphosate, chlorine, or bleach. 

It is made from corn, and the Organic Materials Review Institute has certified it for organic use.

This is a highly corrosive formula, so wear protective clothing when using it and keep it away from pets and children.

Compare-N-Save Concentrate Grass And Weed Killer

Compare-N-Save Concentrate Grass and Weed Killer are made of 41% glyphosate.

Since this weed killer is in a concentrated form, one bottle is enough to cover more than 25,000′ square feet.

It only takes one application to kill weeds down to the roots, and you will see results between 2-4 days.

This product is mixed with water and then poured into a sprayer for easy application.

Always use this weed killer on a warm, dry day with very little wind.

Within two hours of application, this product is unable to be washed away by rain.

A one-gallon container will cover 25,000′ square feet.

Preen Extended Control Weed Preventer

Preen Extended Control Weed Preventer works by creating a barrier just underneath the ground’s surface to prevent weeds from growing for up to six months.

This granular herbicide is best when used in early spring before weeds start to grow. 

However, the product may be used any time weeds are present.

This product can prevent and control more than 600 different weeds, and it is straightforward to apply.

Spread the granules in an even layer to prevent weeds, and then add water to activate them. 

Any granules leftover after watering will continue to disintegrate on their own.

Once the product is completely dry, it is safe for pets and children to walk on.

This product is not meant to be used on grass, and it should not be used near food-producing or edible plants.

A 5-gallon container will treat up to 805′ square feet.

Roundup Landscape Weed Preventer

Roundup Landscape Weed Preventer is safe to use on annual and perennial flower beds, as well as trees and shrubs.

This herbicide is easy to use and has a built-in applicator to ensure you are getting even coverage.

Once the product has been applied, it may be left on the soil’s surface or raked into the top layer for maximum effectiveness.

When you are satisfied with the coverage area, you must add water to activate the herbicide.

This product creates a barrier to prevent weeds, and it will last for up to six months.

Spectracide Weed & Grass Killer

Sectracide Weed & Grass Killer is a non-selective herbicide in a highly concentrated solution.

This powerful weed killer soaks down to the roots, ensuring the weeds do not come back and providing your flower bed with the ultimate protection.

The herbicide is mixed with water, and then a tank sprayer may be used to get even coverage.

Apply this product on sunny days when the temperature is warmer than 60 degrees Fahrenheit.

This product is very fast-acting, and it is rainproof within 15 minutes of application.

You will see noticeable weed death within three hours.

Do not use this herbicide near edible or food-producing plants.

You will be able to plant more greenery one day after application, but it is advised to wait at least seven days if you are planting grass seed or having sod installed.

Preen Garden Weed Preventer

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Preen Garden Weed Preventer does not kill existing weeds, but it is excellent at preventing them for up to three months.

It is a pre-emergent herbicide, meaning it will prevent seeds from germinating, but it will not kill a plant that has already sprouted.

The product is applied to the desired area during warm weather and only reapplied every 9-12 weeks.

This herbicide is also safe to use around more than 200 plant species, including flowers, trees, shrubs, vegetables, and edible plants.

A 30-pound bag of this product will cover about 5,000′ square feet of space.

Fertilome Killzall Weed and Grass Killer

Fertilome’s Killzall Weed and Grass Killer is a non-selective herbicide formulated with 41% glyphosate.

Because this weed killer is so potent that it is not recommended to be used near grass if you do not want to accidentally kill part of your lawn.

The herbicide is applied by spraying, and it dries very quickly and starts working right away.

There will be noticeable weed death within 2-5 days, but more stubborn weeds may take up to one week to die out.

Roundup Weed & Grass Killer Concentrate Plus

Roundup Weed & Grass Killer Concentrate Plus is formulated with 18% glyphosate and 0.73% diquat for its active ingredients.

Preparation is done by mixing the herbicide with water, and then a tank sprayer is used for easy application.

This potent herbicide is safe to use around flowers and shrubs but not existing edible plants.

After the product is applied, it becomes rainproof within 30 minutes.

You will begin to see results in as little as 12 hours.

Weeds are guaranteed not to come back, and they are killed down to their roots. 

Most weeds are completely dead around 1-2 weeks after using this herbicide.

This weed killer is also safe to use on large areas, such as lawns. 

However, because this formula contains glyphosate as its main active ingredient, it is not safe to have pets or small children.

Spectracide Weed & Grass Killer Extended Control

This extended control formula of the Spectracide Weed & Grass Killer starts killing weeds on contact and prevents weeds for up to five months.

This herbicide is rainproof just 15 minutes after application, with visible results within three hours.

It is also possible to plant new flowers or other plants only one day after applying this product.

This weed killer is diluted with water, and a tank sprayer is used for even application.

For the best results, apply this product on a sunny day when the temperature is higher than 60° degrees Fahrenheit (15° C).

Do not use this herbicide in areas you plan to seed within three months.

A 32-ounce bottle will treat up to 3,000′ square feet.

Ortho Weed B Gone Plus Crabgrass Control

This fast-acting herbicide targets over 200 types of broadleaf weeds, including the most common weed, dandelion, as well as stubborn crabgrass.

Ortho Weed B Gone kills weeds down to their roots and starts working within a few hours.

The bottle includes a wand sprayer for simple and even application.

While this herbicide is excellent at killing weeds, it does not work to prevent them.

It is also safe to use this product to kill common weeds on your lawn without harming the grass, as long as the directions are followed.

Doctor Kirchner Natural Weed Killer

Doctor Kirchner Natural Weed Killer is an all-natural, organic weed killer, and it is safe to use around pets and small children.

This product is made using ocean saltwater, commercial strength food-grade vinegar, and soap.

A sprayer is attached to the bottle for easy application.

The manufacturer is based in Ft. Pierce, Florida, and they pride themselves on producing a sustainable, earth-friendly product.

Once the weeds are completely saturated, they will start to die within 12-24 hours.

For stubborn weed varieties, it may take several applications.

Another great feature of this weed killer is its long shelf life. 

Any leftover product may be stored for several years without losing its potency.

Before You Get Started With Weed Killers For Flower Beds

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Before applying an herbicide in your flower bed, it is crucial to understand the product you wish to use and expect the results.

An herbicide in a flower bed needs to be effective enough to kill weeds but safe enough to protect your flowers and shrubs.

You also need to consider the chemical makeup of the herbicide, especially if you have environmental concerns or will be using the weed killer in an area where pets or children play.

Check out our list of weeds that look like grass and how to get rid of them.

Natural or Chemical Herbicide?

It is crucial to understand the ingredients in your herbicide before using it in your flower bed.

Weed killers are either made from all-natural ingredients or a mixture of potent chemicals.

Chemical herbicides will work quickly and efficiently, but their ingredients are more toxic and harmful to the environment.

Some chemicals in these herbicides do not break down easily, and they may even find their way into groundwater sources.

If you have pets or small children, it is best to avoid any formula containing glyphosate and opt for a more natural solution if possible.

Natural weed killers are much better for the environment and much safer to use around children and pets.

They are usually more slow-acting than harsh chemical herbicides, but they may be just as effective at killing and preventing weeds.

Consider your options and do lots of research to decide which type of herbicide will work best for your situation and lifestyle.

By the way, bleach is NOT a good choice.

It will kill weeds…and everything else.

Check out our article on the truth of what bleach does to grass.

The Application Process

How a weed killer is applied should also factor in your decision on which type you would like to use.

Most herbicides are available in concentrated, ready-to-use, and granule formulas.

Concentrated herbicide is the most time-consuming to apply because it has to be mixed with water in the proper amounts according to the label before it is used.

Ready-to-use formulas work directly from the bottle, and these varieties usually come with their sprayer attachment for easy application.

Granule formulas are spread in the area you wish to treat and then watered to activate them.

Choose a formula that will work for you according to the amount of effort you are ready to commit to.

If an herbicide requires a lot of steps to apply, you may not use it as often as you need to.

Choosing a Flower-Safe Weed Killer

An herbicide safe for your flower bed needs to have a balanced formula to work properly.

Weeds will develop a resistance to an herbicide if the same one is used often, so you may need to switch formulas if your regular product becomes ineffective.

It is also important for the ingredients in a weed killer to be compatible with other agrochemicals plants need for healthy growth and development.

The Difference Between Selective and Non-Selective Weed Killers

A non-selective herbicide does not know the difference between weeds and flowers, and its main job is to kill any living plants it is applied to.

When using a non-selective weed killer, you will need to protect any flowers or other vegetation around the application area.

A selective herbicide is a better choice for flower beds, as it only targets the weeds you want to kill and leaves your flowers unharmed.

While selective weed killers tend to be less effective than their non-selective counterparts, you will be able to use them without posing too much of a harmful risk to your flowers.

The Difference Between Pre-Emergent and Post-Emergent Weed Killers

A pre-emergent herbicide kills weeds before they sprout and is mainly used as a weed preventative.

Pre-emergent weed killers will last up to six months, but you will need to pull out any existing weeds before application.

A pre-emergent weed killer is usually applied just before spring before the weeds have a chance to sprout and grow.

A weed preventative will not eliminate a significant weed problem, so do not expect it to kill any weeds you already have.

A post-emergent herbicide is a better option for killing existing weeds in your flower bed, but it will not work to prevent weeds from sprouting up in the future.

You may need to use several applications of a post-emergent weed killer to completely eradicate a large area of weeds throughout the growing season.

Safety Tips For Applying a Weed Killer

It is essential to take several safety precautions when applying weed killer to protect yourself and your family from the harsh chemical ingredients.

When applying an herbicide, you must wear protective gear such as safety glasses, waterproof gloves, long pants, and long sleeves.

You may even want to keep a spare change of clothes handy in case there are any spills.

Always spray away from you and take care not to step in a newly treated area to avoid tracking any chemicals through untreated areas or your home.

Keep children and pets away during weed killer application, and do not allow anyone to walk through a treated area until it has dried.

Remove your shoes before entering your home, and be sure to thoroughly wash your hands with soap and water after herbicide application.

Do not spray herbicide on a windy day, and avoid applying anywhere near water or trees.

If you are using a weed killer on your lawn, be sure the area is watered the day before application.

Applying herbicide during drought conditions will be very stressful to your lawn and may cause your grass to be burned or die.

By following these simple safety procedures, you will be sure your application of weed killer is as safe as possible.

Protect Other Plants

To avoid accidentally killing any plants you do not want to die, you will need to take steps to protect them during herbicide application.

Always spray when there is no wind to avoid any overspray from reaching your flowers.

Use plastic or cardboard to temporarily protect nearby plants, and remove the coverings once the herbicide application has dried.

Be sure to use a dedicated sprayer or watering can avoid accidentally dosing your flowers with a weed killer.

Thoroughly rinse any sprayers or watering cans used for herbicide application, and pour the water away from any areas affected by the chemicals.

Whenever possible, spray the weed killer on a cloudy day, as sunlight will exacerbate any damage nearby plants may have incurred from spray drift.

Targeting Weeds

To avoid any issues that may arise from spray drift, you will need to develop a way to target the weeds directly.

A 2-liter bottle, plastic milk jug, or metal food can with the top and bottom removed to isolate a small patch of weeds.

Simply place the makeshift collar over the weeds you target and spray the entire plant inside the container.

For a large patch of weeds, use a cardboard box to create a targeted area and protect the plants around it.

Weeds on the edge of your flower bed may be isolated by anchoring them to the ground with an anchoring pin. 

This will allow you to spray the pinned weeds without disturbing any of the plant life around them.

Commonly Asked Questions

Is weed killer bad for soil?

While most ingredients in weed killers will dissolve in water and break down over time, glyphosate seems to be the exception to the rule.

In phosphorus-rich soil, glyphosate can leech into groundwater stores.

Some studies have also found glyphosate may stay active in the soil anywhere from six months to one year.

When choosing a weed killer, research the ingredients carefully.

Some chemicals are more volatile than others and may accumulate in the soil.

If you are concerned with the environmental effects, choose an herbicide made with natural ingredients whenever possible.

When should you not use weed killer?

Do not use a weed killer in temperatures higher than 85° degrees Fahrenheit (29° C), and avoid applying any products under full sunlight.

High temperatures and bright sunlight increase the risk of causing burn damage to surrounding areas.

The best time to apply a weed killer is in the early morning hours when the temperature is at least 60° degrees Fahrenheit (15° C).

How long after weed killer can I plant flowers?

Some weed killers say it is safe to plant flowers one day after application, but it is best to wait at least three days to ensure the herbicide has had enough time to evaporate.

If you are concerned about whether or not it is safe to plant flowers after using a weed killer, you may wait at least seven days before planting.

Why is weed killer not working?

Some weed killers lose their effectiveness when they are stored for long periods.

If you have used some leftover herbicide and it did not work, there is a good chance the product is no longer effective.

Freezing cold temperatures or very extreme heat will cause the active ingredients to break down and lose their effectiveness even faster.

Be sure to read the label on your herbicide to learn how the product needs to be stored.