Weeds don’t just ruin the aesthetics of their surroundings, but they’re also quite the thieves; they create a rivalry with other plants, competing over moisture, nutrients, and even sunlight. To become stronger quickly, they deprive other plants of the necessary sustenance so they can grow and flourish.
Active control of weeds is vital for the overall health of your plants. When you eliminate weeds from your flower bed, soil condition is improved, which in turn improves the condition of your plants. Weed killers – when selected carefully – effectively exterminate any weeds harming your flower bed.
A weed killer would be a perfect addition to any DIY gardener’s tool belt, as weeds can be the downfall of many otherwise beautiful and healthy gardens. This guide will help familiarize you with the things you need to know before buying a weed killer, so stick around.
How to Choose a Weed Killer for Flower Beds
Each weed killer has different characteristics and affects different types of weeds. To decide which weed killer will work best for you, you have to familiarize yourself with the types of weed killers out there as well as the types of weeds that grow commonly around flowers.
You also need to learn about the negative impact that some weed killers may have so that you don’t end up damaging your flower beds.
To start, what are the different types of weed killers?
Types of Weed Killers
Weed killers are classified according to their selectivity and time of application.
Some weed killers are selective, whereas others are non-selective. Some are pre-emergent, while others are post-emergent.
Selective vs. Non-Selective
If you plan on treating your flower bed using the blanket application method (applying an herbicide over the whole leaf area), you should know the difference between a selective weed killer and a non-selective weed killer. The distinction between them could either make or break your flower beds.
Selective Weed Killer
A Selective weed killer is simply a chemical that’s developed to affect certain plants, like broad-leaved weeds and grasses. It doesn’t target other plant species even if it comes in contact with them.
When selective weed killers are sprayed, they stick to the smooth surface of the leaves. They create a thin film or an array of small droplets on the plant’s surface, stimulating growth that cannot be sustained. So, essentially, a selective weed killer forces the weeds to grow themselves to death.
The types of plants that selective weed killers target will be written on the product’s label. Other than the specified types, the weed killer will leave the rest of your plants unscathed.
Non-Selective Weed Killer
A Non-Selective weed killer isn’t as merciful to your flower bed as a selective one. As the name suggests, a non-selective weed killer won’t differentiate between those pesky weeds and your harmless flowers.
Non-selective weed killers function by getting rid of all plant life. This type of weed killer can remove a substantial area of weeds regardless of all other plants in that area.
Most non-selective weed killers are made with glyphosate, which is an active ingredient that impedes most plants from producing the protein required for their growth. It binds itself tightly to the soil, ensuring that weeds don’t grow again.
One of the most notable benefits of non-selective weed killers is that they protect the soil from possible erosion.
Pre-Emergent vs. Post Emergent
To completely eradicate weeds, knowing when to apply the weed killer is absolutely crucial. Every weed killer performs differently at certain phases of plant growth and development.
Pre-Emergent Weed Killer
A pre-emergent herbicide is used before the seeds get the opportunity to germinate. It interferes with the growth process of the seed and prevents it from ever developing into a weed.
It doesn’t affect existing roots or established plants, although it is effective on sensitive root tissue, which means any new, young plants may suffer the same fate as the troublesome weeds.
This weed killer should be applied the season before the seeds start to germinate. So, if the type of weed germinates in spring, apply it to the soil in winter.
It may not work on perennial plants that have stubborn roots, and it won’t work on plants that produce seeds all year round, like dandelions.
Post-Emergent Weed Killer
So, those unpleasant weeds have surfaced, now what? Post-emergent weed killers are the solution. These work on already mature weeds that are visible above the soil.
These herbicides mostly come in spray form, and they either attack the weeds’ leaves or flow down to the roots, impeding the weeds’ growth once and for all.
There are two types of post-emergent weed killers: systemic and contact.
Most ideal for perennial plants, the systemic weed killer gets absorbed into the entire structure of the weed. This effectively kills the whole plant.
The contact weed killer, on the other hand, impacts the exposed parts of the weed, preventing it from photosynthesizing. It’s effective in eradicating small and annual weeds.
Which Weeds Are Most Common Around Flowers?
No one can resist the beauty of flowers. Sadly, this beauty sometimes invites pesky, unwanted guests.
There are some common weeds that just love to grow around flowers. It’s important that you’re able to identify them so you can use the appropriate weed killer.
Bermudagrass is a notoriously aggressive weed that poses serious problems once it establishes itself in any soil. It’s a perennial plant, which means that it won’t die with the change of seasons.
The key reason for bermudagrass’ notoriety is its runners, which are basically the long stems that grow horizontally.
Bermudagrass runners create joints at regular intervals that give way to two or three side shoots. Every shoot becomes its own runner, putting out its roots and creating a supply channel for moisture and nutrition.
The side shoots continue to shoot and expand until they completely cover the area they’re in. Any competition is ultimately eliminated.
Luckily, this territorial dominance isn’t as daunting if the bermudagrass doesn’t get sufficient water, nutrients, and sunlight. In these conditions, the runners don’t take root in flower beds, especially if they’re covered in mulch.
Stubborn and patient, sedge is a perennial plant that can stay dormant for years and years until it finds the right conditions to grow.
Its waxy, smooth leaves are thick and stiff. Its stems are triangular and yellow, which makes it easy to spot among other plants. It often grows vertically, arching at the tip.
It won’t desiccate in the heat of the summer thanks to its ability to withstand any and all weather conditions. No matter how wet, dry, fertile, or barren the soil is, the tubers can lie idle awaiting proper nutrition.
Once they settle in the soil, it becomes very difficult to control and get rid of them. If you pull out the plants but not the tubers, they’ll just sprout new ones and re-emerge.
An annual summer weed, spurge grows quite rapidly in high temperatures. It can become a problem pretty quickly if left untreated. This weed isn’t only a problem for flower beds, but also can be a problem for humans and animals.
The seeds of spurge germinate in the soil and start to grow once the temperature reaches 60 degrees Fahrenheit. Their rapid growth causes them to outperform other plants in the same bed.
Spurge is characterized by the milky sap that oozes out of it when broken. Be careful as the sap causes irritation to the skin and might be deadly if consumed.
Flower beds with mulch make the best environment for spurge. The mulch decomposes rich organic matter, which forms the perfect soil for the growth of this weed.
The lambsquarter weed was once loved for its edible leaves, but it’s now best to avoid letting it grow around your flowers, as these weeds carry viral diseases that can destroy the plants surrounding them.
The key to its survival is its ability to produce tens of thousands of seeds per plant. If left to grow, you’ll find yourself struggling with several generations of weed.
The telltale characteristic that identifies lambsquarters is the white, dusty coat on the lower side of their leaves.
Taking care of the lambsquarter weed early on is crucial. It has a short taproot, so you can remove it easily before it becomes mature enough that it produces seeds.
Dandelions are probably the most well-known weeds out there. They’re perennial plants that can thrive just about anywhere.
When the unmistakable yellow flowers mature, they grow golf-ball-sized seed heads full of hundreds of seeds. These seeds are carried by air, which allows them to spread over an extensive area.
Dandelions’ ability to take root anywhere makes them incredibly capable of survival. They grow fast, transforming from bud to flower in only a few days. As beautiful as they are, their rapid growth rate and their efficient seed heads can make them overwhelm your flowers.
Do Weed Killers Harm Flowers?
Although there are weed killers that are selective and target specific types of plants, there are some cases where the weed killer may harm your flowers.
Even if it’s unintentional, the moment the weed killer comes in contact with the flowers, they’ll start to change colors, or their growth may be hampered.
How to Choose the Best Weed Killer for Your Flower Bed
The impact of the weed killer depends on its water solubility. Weed killers that have low adsorption levels dissolve in water. That means that they’ll be able to move within the environment and soak into the soil.
The weed killer’s persistence in the soil is relatively determined by its half-life, which can be affected slightly by soil and weather conditions.
The way the herbicide will behave in a body of water is dependent on its water solubility. If it’s dissolvable, it’ll remain in the water until it’s degraded.
Note that alkaline water may change the way the weed killer behaves, altering its effect.
There are different ingredients in every weed killer. Each ingredient serves a different purpose. Some of the most notable ingredients in weed killers include glyphosate, acetic acid, and clethodim.
- Glyphosate is a non-selective, systemic post-emergent weed killer. It impedes most plants from producing the protein required for their growth. It binds itself tightly to the soil, which ensures that plants can’t grow again.
- Acetic acid is an organic option for those who don’t want to use chemicals. It’s a vinegar-based weed killer that eradicates weeds by increasing the soil’s acidity.
- Clethodim works well for annual and perennial weeds. It’s a selective and post-emergent weed killer. It’s harmful to aquatic animals, so it should be applied with caution near bodies of water.
Every weed killer works for a specific amount of time. Most product label tags will tell you how long the weed killer will remain effective in your soil.
The rain may spread certain weed killers to other plants and areas, so try to avoid applying them during rainy days.
Weed killers are chemicals formulated with the intent to eradicate a living organism. That said, it’s important to make sure that the weed killer you’re about to buy doesn’t pose any risk to the flowers in your bed; only the weeds.
Additionally, make sure to keep away any children or pets from the area that’s going to be sprayed. Further, you should wear protective gear while spraying, and you should avoid over-spraying so that you don’t end up damaging the soil.
The Top 7 Reviewed Weed Killers For Flower Beds
#1. Compare-N-Save Concentrate Grass & Weed Killer
- Rainproof in 2 hours
- Visible results in as little as 2 to 4 days
- Contains 41-percent glyphosate
The Compare-N-Save Concentrate Grass & Weed Killer is our top choice for a weed killer to use in and around your flower beds. The concentrate is made from a solution of 41% glyphosate, which is a post-emergent herbicide. This means it will not prevent any new or future growth of your plants or vegetables; in fact, treated areas can be replanted in as little as one day. Glyphosate is absorbed through a plant’s foliage and then travels down to the root to kill the weed, so avoid spraying any plants or flowers you don’t want to treat.
This herbicide is highly concentrated and will kill any green plants you use it on, including lawn grass. All it takes is 1.5 ounces of the concentrate to mix with an entire gallon of water, or for tougher weed control use 2.5 ounces to 1 gallon of water. This means one container of the Compare-N-Save can give you up to 85 gallons of usable herbicide, and can cover over 25,000 square feet of garden. WIth visible results in as little as two days, and rainproof within 2 hours, with this weed killer you can treat your entire lawn or garden in no time.
#2. Doctor Kirchner Natural Weed & Grass Killer
- A natural weed killer Made from ocean salt water, commercial strength food grade vinegar and soap.
- Our non selective ready to spray Natural Weed & Grass Killer is not normally used on the lawn.
- No Mixing, No Glyphosate and No Hormone Disrupting Chemicals
The Doctor Kirchner Natural Weed & Grass Killer is a powerful, all-natural weed killer that is safe for your garden as well as the environment. The only ingredients it contains are ocean water, food grade commercial vinegar, and a pinch of soap. It is both pet and child friendly and causes no harm to the planet, and it does not come with any glyphosate or hormone disrupting chemicals.
This Weed & Grass Killer is very simple to use – all you have to do is spray the weeds you want to kill to the point of wetness. It works fast as well, with most weeds starting to wither in less than a few hours, and even the longest, most stubborn weeds turn brown within 12-24 hours. It is a non-selective spray, so make sure you don’t coat flowers or plants that you don’t want to treat. Additionally, this weed killer will last for many years as it doesn’t have any ingredients that will degrade, so it will save you time and money in the long run.
#3. Preen Extended Control Weed Preventer
- 1 Application blocks weeds up to 6 months
- When used as directed Preen Extended Control Weed Preventer can be used around more than 600 perennials, groundcovers, shrubs and trees as listed on the product label
- Can be sold as a refill for flip-top applicator bottle
The Preen Extended Control Weed Preventer is perfect if you have a garden that is currently free of weeds and you want to keep it that way. It is not a weed or grass killer, so it does not kill any pre-existing weeds and you will need to remove any weeds that are currently in your garden by hand, taking care to remove the entire root system as well. However, one single application will prevent and block 125 types of broadleaf and grassy weed growth for up to 6 months, so as long as you apply this weed preventer in your garden twice a year, you won’t have to worry about weeds ever.
It is very simple to apply as well, as all you have to do is lay down a three-inch layer of mulch, apply the Preen Extended Control over it, and water the soil. This weed preventer can be used within and around flower beds with over 600 established plants, including many common garden plants. It works best when applied in Spring, before weeds start to grow, but can be applied any time throughout the year and still be effective. Additionally, one bag can cover up to 3,500 square feet of garden soil.
#4. Green Gobbler 20% Vinegar Weed & Grass Killer
- KILLS WEEDS & GRASS FAST - Eliminate any type of weed in just a matter of hours. Expect full desiccation in less than 24 hours. Green Gobbler contains 20% acetic acid. Use on crabgrass, dandelions,...
- SAFE TO USE ANYWHERE - Perfect for residential, commercial, industrial and agricultural use. Apply where weeds and grasses are not desired. Use on driveways, sidewalks, concrete, mulch beds, pavers,...
- CERTIFIED FOR ORGANIC USE - Completely eliminates and desiccates weeds and grasses without using toxic chemicals. Made straight from corn. OMRI listed weed killer and certified for organic use.
The Green Gobbler 20% Vinegar Weed & Grass Killer is another fully natural and organic weed killer that does not use glyphosate or any hazardous chemicals at all. It is an OMRI listed certified organic weed killer that uses Acetic Acid as its only active ingredient. Also called Ethanoic acid, this is a naturally distilled ethanol from corn, and is basically vinegar but 4 times the strength. Therefore this weed killer is safe to use anywhere weeds are not wanted, like driveways, sidewalks, mulch beds or flower beds, or anywhere in your lawn or garden.
You can use the Green Gobbler on all types of weed as well, such as dandelions, clovers, crabgrass, moss, musk thistle, and many others. It works very quickly and easily – all you have to do is spray it on the affected area, and within 24 hours it will be all dried up! And it can do all of this without being potentially harmful to your children, pets, the environment, or yourself. Green Gobbler also has a 30-day money back guarantee if you’re not completely satisfied with their products.
#5. Ortho Weed B Gon Plus Crabgrass Control
- Kills crabgrass, dandelions and other common lawn weeds
- Kills weeds to the roots
- Kills 200+ weeds
The Ortho Weed B Gon Plus Crabgrass Control is a highly effective weed killer that comes with a Comfort Wand that can easily spray any affected area, and is accurate enough to work around your normal garden plants and flowers. When used as directed, it is guaranteed to not harm your lawn. It can be used on any of the common grass types you would find in your yard, including Bermudagrass and Zoysiagrass, and kills 200+ types of weed, including all the major broadleaf and grass weeds, as well as crabgrass.
The Weed B Gon starts acting immediately when applied. It is rainproof within 1 hour, and you can start seeing results within hours. With the easy application comfort wand and the convenient trigger applicator, you can only spray exactly what you need to remove, and it can be reused with a refill bottle so you won’t have to buy a new weed killer every spring.
#6. Spectracide Weed & Grass Killer Concentrate
- KILLS WEEDS AND GRASSES: use on driveways and walkways, and around fences, trees, flower beds, shrubs and other areas in your yard
- KILLS THE ROOT: visible results as fast as 3 hours – replant new flowers, trees and shrubs the same weekend
- RAINFAST: rainfall or watering 15 minutes after application will not wash away effectiveness
The Spectracide Weed & Grass Killer Concentrate is great at killing weeds and unwanted garden grasses, and can be used in a variety of applications. Firstly, you can use it when first renovating a garden to remove any and all grass, weeds, and plants, and then to start over with a fresh plant from scratch. It works quickly – you can start to replant only one day after spraying, and you will start to see visible results within 3 hours. It is also rainproof within 15 minutes of spraying.
You can also use the Spectracide Weed and Grass Killer around ornamental trees and plants and any lawnscaping you already have. Any plants you don’t want to be treated you simply cover with cardboard and spray around them. We wouldn’t recommend using this for spot treatment on your lawn, however, since it will kill any green grass it might spray.
#7. Preen Garden Weed Preventer
- Stop weeds before they start for up to 3 months guaranteed
- Safe for use around over 200 established flowers, vegetables, trees and shrubs
- Can be sold as a refill for flip-top applicator bottle
The Preen Garden Weed Preventer is another preventer that works to stop weeds from growing in the first place rather than killing them off. This Preen product stops weeds before they start for up to three months, and a single bag can cover up to 5,000 square footage of your garden, which means you can use it many times over multiple years. It is safe for use with over 200 established vegetables, plants, flowers, and trees, including edible plants and vegetables.
Although it does not kill existing weeds, you can use the Preen Garden Weed Preventer at any time during the spring, summer, or fall. All you have to do is remove the current set of weeds (don’t forget to get the roots!), apply mulch and a layer of Preen, and water. That’s all there is to it! It will then protect your garden from a whole variety of broadleaf and grassy weeds, like knotweed, thistle, chickweed, and crabgrass.
We hope you were able to help you find the best weed killer for your own specific lawn or garden. If you are still searching, we again recommend the Compare-N-Save Concentrate because it is very effective and covers by far the most area of any of the weed killers on our list.
If you need an organic weed killer, however, the best you can find is the Doctor Kirchner Natural Weed Killer, which is made only from ocean water, vinegar, and soap.