How to Choose the Right Weed Killer

Use herbicides to eliminate weeds and create a beautiful, healthy yard

Weed Killer

Weed killers, also known as herbicides, and weed preventers are important tools for every gardener, no matter the shade of their green thumb. Resist the urge to pull weeds by hand – they will grow right back if the entire root isn’t removed. The most effective ways to deal with weeds in your lawn, gardens or landscapes is to prevent them from growing in the first place and kill the ones that do pop-up down to the root.

Weed killers contain chemicals that kill plants or inhibit their normal growth. The best weed killer depends on what types of weeds you are trying to eradicate. Herbicides vary according to their effects – some aim to kill weed seedlings while others kill weeds after they are up and growing.

This guide highlights the different types of available weed killer, along with application recommendations.

Types of Weed Killers

Types of Weed Killers

There are four basic characteristics that describe how all herbicides work: emergence, selectivity, persistence and translocation. Understanding the importance of each characteristic will help you read product labels and properly select the weed killer that’s best for your yard. 


Weed killers are either pre-emergence, which target germinating seedlings before they grow, or post-emergence, which work on weeds that have already started growing. Apply pre-emergent two to three weeks before the weeds germinate and apply post-emergent to the leaves of the plant.


Weed killers are either selective, which kill weeds without damaging nearby plants, or non-selective, which generally kill all plants in the vicinity of application. Use a selective herbicide to kill dandelions without damaging your lawn, and a non-selective herbicide to kill weeds growing in sidewalk cracks.


Persistence describes how long the herbicides remain active after application. Those that provide no lasting prevention of weed growth are called non-persistent. Those that kill everything and prevent regrowth are persistent.


Herbicides work their way through a plant’s internal system to break it down, while contact herbicides kill plants on contact.

How to Kill Weeds in Lawns

How to Kill Weeds in Lawns

Treating weeds springing up in your lawn is tricky – you want to eliminate the weeds but keep the grass lush and undamaged. Use a weed control product that has been specifically designed for use in lawns.

Apply weed prevention products to your lawn in early spring or late summer before weeds germinate. Weed killers that eliminate dandelion, clover, crabgrass and nutsedge should be applied when weeds are actively growing in the late spring or late summer.

How to Kill Weeds in Gardens

How to Kill Weeds in Gardens

When a weed appears in your landscape beds, including mulched tree rings, you must kill it quickly to prevent it from spreading. But be mindful not to harm surrounding plants or damage the soil so it cannot nourish future plants you may want to grow.

Pre-emergent control products stop weed seeds from sprouting – check the label for a list of specific weeds. Apply before the weeds germinate in early to late spring for best results.

A post-emergent control product is typically non-selective and will help you kill both grassy and broadleaf weeds quickly. When applying, be careful to avoid any desirable plants as a non-selective product kills anything green and actively growing.

How to Kill Weeds in Driveways and Patios

How to Kill Weeds in Driveways and Patios

While it may be tempting to simply pull weeds to sprout in driveway cracks or any other hard surface in your landscaping, that will not completely prevent them from growing back.

Apply combination pre- and post-emergent control products to these unwanted weeds. These herbicides quickly kill weeds growing in hardscapes and deposit chemicals that prevent new weed growth.

How to Kill Poison Ivy and Tough Brush

How to Kill Poison Ivy and Tough Brush

Noxious weeds like poison ivy, poison oak, kudzu and other tough brush love to invade landscapes. These tough weeds require a specialty weed control product to kill.

Use a post-emergent control specially designed to treat tough brush for fast elimination. These are typically non-selective control products, so be careful to avoid any plants that you want to keep alive.