Broadleaf Weed Control for Cool-Season Lawns

Written By Ian Danner

What Works, What Doesn’t, and When to Apply

⚠️ First — the label is the law (always)

Before discussing any product, timing, or recommendation, this must be said clearly:

The label is the law. Always read and follow the label.

That includes:

  • Application rates

  • Required personal protective equipment (PPE)

  • Weather and temperature restrictions

  • Wind limits

  • Re-entry intervals

  • Turfgrass species tolerance

  • State-specific restrictions

No blog post, forum comment, or recommendation replaces the label.

Special note on dicamba

Products containing dicamba deserve extra caution:

  • Dicamba is volatile

  • It can move off-target, especially in warm conditions

  • Wind speed, temperature, and nearby ornamentals matter

Misuse can damage neighboring plants, shrubs, and trees. Always confirm:

  • Wind speed

  • Temperature limits

  • Application method allowed on the label

If you’re not comfortable spraying products with volatility concerns, stick with lower-risk options or granular formulations.

Why pre-emergents don’t stop most broadleaf weeds

One of the most common lawn care misunderstandings is assuming spring pre-emergents prevent everything.

Most pre-emergents are designed to prevent grassy weeds like crabgrass. Many broadleaf weeds:

  • germinate in fall,

  • overwinter as small plants,

  • and explode in spring using stored energy.

By the time you see them, they are already established, which is why pre-emergents don’t stop them.

The most common broadleaf weeds in cool-season lawns

  • Dandelion

  • White clover

  • Plantain

  • Chickweed

  • Ground ivy (creeping Charlie)

  • Oxalis (wood sorrel)

These are controlled post-emergence, not prevented like crabgrass. Check the Label for all controlled plants.

What actually controls broadleaf weeds

1️⃣ Three-way broadleaf herbicides (most common option)

Most homeowner products use a combination of:

  • 2,4-D

  • Dicamba

  • MCPP or MCPA

Controls well:

  • Dandelion

  • Plantain

  • Chickweed

  • Many annual broadleaf weeds

Best timing:

  • Spring while weeds are actively growing

  • Fall (best long-term control)

Fall applications work best because weeds are moving carbohydrates to the roots — pulling the herbicide with them.

2️⃣ Triclopyr (for tough perennial broadleaf weeds)

Some weeds resist standard 3-way products.

Best for:

  • Ground ivy (creeping Charlie)

  • Wild violet

  • Clover (better suppression)

This is one of the most effective tools for stubborn perennial broadleaf weeds when used correctly and legally.

3️⃣ Mesotrione (Tenacity-type products)

Mesotrione is a specialty tool, not a replacement for standard broadleaf control.

Strengths:

  • Can be used at seeding

  • Suppresses some broadleaf weeds

  • Controls certain grassy weeds

Limitations:

  • Short residual

  • Not strong on mature dandelions

  • Often requires repeat applications

Best used during renovation or overseeding — not as a one-product solution.

Spray vs granular applications

Spray applications (most effective)

  • Better leaf coverage

  • Faster results

  • Ideal for spot treatments

Granular weed-and-feed products

  • Convenient

  • Less precise

  • Often apply unnecessary nitrogen

Granular products can work, but convenience comes at the cost of control.

Timing matters more than brand choice

Spring

  • Works on young, actively growing weeds

  • May require follow-up applications

  • Avoid spraying during large temperature swings

Fall (best window)

  • Strongest control of perennial broadleaf weeds

  • Fewer applications needed

  • Better results the following spring

If you only spray once per year, fall is the best choice.

Long-term prevention: turf density

There is no true “broadleaf pre-emergent” substitute for:

  • Proper mowing height

  • Correct nitrogen timing

  • Overseeding thin areas

  • Improving sunlight and drainage

Thick turf is the real prevention strategy.

Safety equipment matters (don’t skip this)

Always use:

  • Chemical-resistant gloves

  • Eye protection

  • Measuring tools

  • Dedicated sprayer equipment

Bottom line

  • Broadleaf weeds are controlled post-emergence

  • Labels dictate legality, safety, and success

  • Three-way herbicides handle most issues

  • Triclopyr solves the tough ones

  • Fall applications deliver the best results

  • Healthy turf is the best prevention

This article will be updated periodically as new tools and products are evaluated.

Ian Danner
Next

Seed Selection Guide