How to Control Broadleaf Weeds

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close-up of a broadleaf weed in mulch

Whether you have a few broadleaf weeds in your lawn or an army of them, it is possible to control broadleaf weeds in your lawn. So, get on your gardening gear, and let’s get started.

What is a weed?

A weed is a plant that: 

  1. You didn’t plant, and 
  2. Is out of place in your lawn 

Some homeowners want to get rid of weeds so they don’t compete with the grass for nutrients, sun, space, or water. Weeds also may provide a home for insects or harbor disease. All of these factors make weed control an important consideration for a healthy lawn.

But there’s another side to this story. Not all weeds are harmful to the health of your lawn. Some weeds fix nitrogen in the soil, act as indicator species in the lawn, and reduce erosion. In addition, many broadleaf weeds have historically been used for food, drink (ale, anyone?), and medicinal treatments. 

Whether you want that perfect-looking lawn or don’t mind a few weeds here and there, there are ways to reduce these unwanted visitors in your lawn.

What is a broadleaf weed?

close-up of broadleaf plantain weed
F. D. Richards | Flickr | CC BY-SA 2.0

There are two major weed categories: broadleaf and grassy. Broadleaf weeds have wider leaves and are easily distinguished from the grass in your lawn. Grassy weeds, well, look like grass. Here are a few other distinctions:

Broadleaf weeds:

✓ Are dicots (two-leaved seedlings)
✓ Wide leaves
✓ Netted veins

✓ Common broadleaf weeds: Henbit, dandelion, white clover, purslane, spurge

Grassy weeds:

✓ Are monocots (one-leaved seedlings)
✓ Narrow leaves (blades)
✓ Parallel veins
✓ Common grassy weeds: Goosegrass, crabgrass, dallisgrass, foxtail weed, wild proso millet

Why do I have broadleaf weeds in my lawn?

Because you have dirt. It’s that simple.

Broadleaf weed seeds live in your soil and can persist for 30 years (or longer) before they sprout. And weed seeds don’t just live in your soil. There are other ways that weed seeds will spread to your lawn. 

Weed seeds spread by:

  • Wind
  • Animal droppings
  • Low-quality turfgrass seed
  • Topsoil
  • Compost
  • Debris from your shoes
  • Roots

Don’t get discouraged just yet. Even if 100% control isn’t realistic, there are things you can do to reduce the weed population in your lawn over time.

How to control broadleaf weeds

1. ID your weed

close-up of rose clover
Jean and Fred | Flickr | CC BY 2.0

Before you break out the weed killer, let’s learn a few things about your weeds. Knowing the weed species in your lawn is very important. As we mentioned earlier, weeds are indicator species, meaning they often tell you what’s going on in your lawn. 

  • Clover: Thrives in areas with low nitrogen, soil compaction, low pH, and too much or too little water
  • Dandelion: Lives in compacted, low pH soils and indicates that your lawn has low calcium and excessive potassium
  • Ground ivy: Is found in areas with poor drainage
  • Plantains: Indicate compacted soil, a mowing height that is too low, low pH, infertile soil, and poor drainage

From these examples, you can see that there are simple cultural practices that will help control these lawn weed populations. If your weed likes compacted soil, aerate the soil. If you reduce the soil compaction, that weed might choose another place to live. 

Does your weed thrive in wet soil? Aerate and topdress the lawn, or create a rain garden in that area. What about nutrient levels? If your weed indicates a nutrient imbalance, take a soil sample to your local Cooperative Extension office and have them run a soil test so you can correct those imbalances.

infographic explaining how a rain garden works

How can I ID my weeds? Look online for your state’s Cooperative Extension website. They often have Weed ID guides with photos to help you identify common weeds in your state. Or, snap a photo via your favorite plant app.

2. Take care of your grass

In addition to identifying your weeds, there are other simple steps you can take to improve the health of your grass. 

The age-old adage, “A full, healthy lawn is the best defense against weeds” is still true. To prevent weeds in your lawn, give your grass and soil what they need to stay healthy, and your lawn will do most of the weed control for you. 

Mow correctly: Are you mowing at the correct height for your species of grass? Each grass species has a mowing height that helps it grow full and healthy. Also take into account whether your grass is in the shade or if it’s the hottest part of the year (mow higher in both cases).

Finally, don’t forget the one-third rule of mowing: Remove no more than one-third of the grass blade per mow, and leave the clippings on the lawn. (Don’t worry, they won’t contribute to thatch buildup.)

Water well: Watering can have a huge impact on your lawn. Homeowners often make the mistake of watering at the wrong time of day. When should you water your grass? It’s important to water early in the morning, no later than 8 a.m. Grass that is wet for too long is an open invitation for harmful fungi. 

Many people water too much and too often. Most experts say to wait until the lawn looks stressed before you water, and water no more than once per week. (Exception: This may vary depending on your soil type. Sandy soils, for example, need to be watered every few days but with less water per session.)

Signs of drought stress:

  • Folded blades of grass
  • Loss of color — may turn bluish-gray
  • Traffic patterns remain on the lawn (foot or vehicle traffic)

Once you notice that 30%-50% of the lawn looks stressed, it’s time to turn on the faucet.

Aerate: Many weeds love compacted or poorly drained soils. Aeration improves both of these ailments. 

illustration showing how aeration works and the benefits of aerating soil
  • What is aeration?: If you’ve ever seen a lawn that looked like it had pellets strewn across it, they may have had their lawn aerated. A core aeration machine removes plugs of soil from the lawn to open up channels in the soil. This allows more light, air, and water into the soil. The result? Deeper roots and a healthier lawn.

Dethatch: Thatch over ½ inch can reduce water filtration and lead to insect problems. 

illustration explaining thatch on grass
  • What is thatch?: Thatch is a layer of debris between the grass and the soil. If it gets too deep, water and nutrients don’t reach the soil’s surface as well. 

You can use a manual rake for small areas or rent a machine if the whole lawn needs renovating. For minor thatch issues, aeration may be sufficient since you’ll be removing some thatch as you go.

Fertilize: Get a soil test every few years to make sure you’re on track. In the years you don’t do a soil test, follow your state’s lawn care maintenance calendar for fertilizer tips for your grass type. 

3. Know its growth cycle

Reducing weeds in your lawn is like knowing when the game is going to start. If you don’t know what time the game is scheduled to begin, you may walk in at halftime and miss your opportunity to play. 

There are three major types of broadleaf weeds: annual, biennial, and perennial.

Annual broadleaf weeds: Think of annual weeds like an annual plant. It germinates, grows, sets seeds, and dies within one year. Summer annuals live from spring to fall. Winter annuals sprout in late summer, survive the winter, and flower in the spring. 

Example: Lambsquarters is an annual weed.

Biennial broadleaf weeds: Biennial weeds germinate and put down roots and leaves the first year. After overwintering, they set flowers, go to seed, and die.

Example: Musk thistle is a biennial weed. (Can be a winter annual in some climates.)

Perennial broadleaf weeds: Perennial weeds live for three or more years. Although some of these weeds produce seeds, many persist via stolons, rhizomes, bulbs, or tubers. These weeds are the most challenging to get rid of. 

Example: Broadleaf plantain is a perennial weed.

Why does this matter? In nature, timing is everything. If you want to put down a pre-emergent for a summer annual, you need to know that it starts its life cycle in the spring so you can time your application just right. If your weed is a winter annual, you need to put down a pre-emergent in the late summer or early fall to prevent the seed from sprouting.

  • What is a pre-emergent? A pre-emergent is a substance that stops plant seeds from germinating (sprouting). It must be applied before the weed’s life cycle begins.

4. Natural and chemical treatments

So, here’s what we know so far: 

  • We know what kind of weed we have (and what that tells us about our lawn)
  • We know how to better take care of our lawn’s routine maintenance
  • We know our weed’s growth cycle

While you are implementing these good maintenance practices, you may want to know if there are other steps to take to get rid of these weeds. 

Here are a few natural and chemical options to kill broadleaf weeds:

Natural treatments for broadleaf weeds

  • Hand-pull: Use your hand, a screwdriver, or a trowel to pull the weed (roots and all) from the ground. Removing all of the roots (above and below ground) is critical for perennial weeds. And if you plan to hand-pull a seed-bearing weed, do it before the plant flowers to prevent it from sending a new generation of seeds back into your lawn. 
  • Use a natural pre-emergent: If summer annual broadleaf weeds are putting up a fight this year, put down a pre-emergent before they sprout next spring. Corn gluten is a popular chemical-free pre-emergent.
  • Mow: Prevent tall annual weeds from going to seed by mowing over them regularly. If you have a perennial weed that grows from its roots, mowing will weaken and stress the weed, but it will continue to re-grow each year. Competition from nearby grass, hand-pulling, and healthy soil may reduce or eliminate these weeds eventually.
  • Correct lawn imbalances: As we mentioned earlier, weeds often thrive in lawns with compacted soils, nutrient imbalances, or soils that are too wet or too dry. Correct these imbalances to prevent weeds from thriving in your lawn.

Pro Tip: If you have bare spots in the lawn, overseed these with new grass at the proper time of year.

Chemical treatments for broadleaf weeds:

Caveat: The label directions are the law. Always follow the manufacturer’s instructions for your safety and the health of your lawn. 

When you buy a chemical herbicide, make sure it’s formulated to treat broadleaf weeds and is safe for your grass type. 

  • Pre-emergence herbicide: Put this on the lawn before the weed germinates. Most of these products are granular. Note: Timing is critical. Contact your local Cooperative Extension service for the timing in your area, and check soil temps here.
  • Post-emergence herbicide: These herbicides kill the weeds after they’ve germinated. Choose a selective herbicide to avoid killing the grass as well as the weed. Or, use a non-selective herbicide for weeds that grow through the pavement or are otherwise not near vegetation. 

When to apply a post-emergent: Fall or late spring when weeds are actively growing and air temps are more moderate. Avoid applications if the turf is drought-stressed.  

FAQ

1. Where can I get my soil tested?

Your local Cooperative Extension office is a great resource. Your local office can help you with everything from taking a soil sample to sending it into the state lab.

2. Are there other ways to get rid of broadleaf weeds naturally?

Two other options you may have heard of are propane weed burners and horticultural vinegar

3. How do I get rid of weeds forever?

Unfortunately, this isn’t possible, but with consistent effort, you may find that your weed population declines over time. Weed seeds can persist in the soil for one year or several decades, depending on the species. Remember, broadleaf weed control is a marathon sport. It may take several seasons of persistence to see the results you want.

If you’re more of a sprinter, let our local lawn care professionals take your place in the marathon against weeds. 

Main Photo Credit: NY State IPM Program at Cornell University | Flickr | CC BY 2.0

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