How to Identify and Kill Broadleaf Weeds

The path to killing broadleaf weeds in your lawn begins with understanding their life cycles. Depending on whether you’re dealing with annuals, biennials or perennials, you may need to take a different approach to take back your yard.

Here’s how they differ.

Annual weeds. These types of broadleaf weeds live for only one season and are typically easy to control because they lack the complex underground structures needed to spread new plant growth through creeping roots. Still, annuals produce tons of seeds that can infest and dominate your yard under the right conditions.

Summer annuals. These weeds begin to grow (germinate) in the spring, mature in the summer, and then produce seeds and die by the fall or first hard frost—an entire life cycle completed within 12 months.

Winter annuals. These weeds overlap two calendar years but last only 12 months total. They germinate and develop from late summer to early fall, remain semi-dormant during the winter and then flower in spring. Come late spring or early summer, they mature and die off as the weather warms.

Perennial weeds. These types of broadleaf weeds can germinate and spread from seeds, but they also produce a root structure (tubers, bulbs or corms) that can birth new weeds from your lawn’s surface (using stolons) or from underground (using rhizomes).

Biennial weeds. These flowering plants generally live for two years. The first year consists of leaves, stems and root growth, followed by winter dormancy. In the second year, biennials flower and produce seeds, thus completing their life cycles.

The best way to control broadleaf plants is to keep your lawn so dense and healthy that they never grow at all. But if these weeds are already invading your outdoor recreation and relaxation space, here’s how to choose the best broadleaf weed killer.

What’s the Best Weed Control?

Fertilization. The right type and application method makes all the difference. Mowing. Mow frequently at the recommended height with sharpened blades, removing only one-third of the leaf blade. Watering. Water deeper rather than more frequently when rainfall is scarce. Changing. Factor in climate, sunlight, shade, etc., to pick the right turf grass. [Links to J.5 Turf Grass Selection Module]

Does Pulling Weeds Work?

Hand-pulling broadleaf weeds can work if there are only a few, especially if they’re annuals. Perennial weeds are harder to control by hand because you don’t always pull up the vegetative structure that sprouts new weeds.

What Is Herbicide Selectivity?

Postemergence herbicides control existing weeds. They can either be systemic— i.e., moving throughout the plant so that roots, leaves and stems are all affected— or contact—i.e., where only the surfaces suffer (which is enough for annuals). Preemergence herbicides control weed seeds only—not existing weeds. They work on most seed-based annuals and perennials.

What Is Herbicide Selectivity?

Selective herbicides work on specific plants while causing little to no harm to other plant types—e.g., controlling only broadleaf weeds while not harming your lawn. Non-selective herbicides damage a large range of plants, including lawn grasses, so they’re typically used to clear landscape beds or all vegetation. TruGreen® uses a selective systemic broadleaf weed killer as part of our weed control program for your lawn, which ensures the product moves throughout the weed, killing it completely, root and all. Depending on variables such as weed type and time of year, some weeds may require multiple applications.