How to Kill Broadleaf Weeds in Your Whole Lawn

Use a 3-way selective broadleaf herbicide such as Weed B Gon, which contains 2,4-D, MCPP (mecoprop), and dicamba and kills over 250 broadleaf weeds down to the root without harming your lawn grass. For a whole lawn, the easiest method is a hose-end sprayer: set the dial to 2 ounces, add the concentrate (no water, the sprayer meters it), and spray until the lawn surface is lightly wet. The rate for Northern lawns is 2 fluid ounces of concentrate per gallon of water per 500 square feet. Spray on a calm, mild day (45 to 90 degrees) when the weeds are actively growing, avoid drift onto gardens and trees, and do not mow for 2 days before or after. You will see results in about 24 hours, with full kill in 1 to 2 weeks.

No, not when used as directed on the listed lawn grasses. Weed B Gon and similar 3-way broadleaf herbicides are selective, meaning they are designed to kill broadleaf weeds while leaving common lawn grasses like Kentucky bluegrass, fescue, and ryegrass unharmed. The key phrases are as directed and listed grasses: you must apply at the correct rate (not doubled up), in the right conditions (45 to 90 degrees, not in a heat wave), and only on tolerant grass types. Notably, it should NOT be used on bentgrass lawns, on newly seeded lawns until they have been mowed several times, or on grass types not listed on the label. Applied correctly on an established, tolerant lawn, it targets the weeds and leaves your grass standing.

It controls over 250 broadleaf weeds, which covers the vast majority of the wide-leaf weeds you will see in a lawn. Common ones include dandelion, white clover, plantain, common chickweed, henbit, oxalis (yellow woodsorrel), ground ivy (creeping charlie), wild violet, purslane, and many more. What it does NOT kill is grassy weeds, because those are not broadleaf. Crabgrass, foxtail, goosegrass, nimblewill, and other grass-like weeds are unaffected by broadleaf herbicides and require different, specific products. Nutsedge, a sedge with triangular stems, also needs its own herbicide. So Weed B Gon handles the broadleaf category comprehensively, but it is only one piece of total weed control.

Yes, and it is the easiest way to blanket-treat a large lawn. A hose-end sprayer attaches to your garden hose and automatically meters the concentrate as water flows through, so there is no pre-mixing. With the Ortho concentrate, you set the dial to 2 ounces (for Northern lawns), pour the concentrate into the sprayer jar without adding water, connect the hose, and spray until the lawn surface is just wet. The alternative is a tank or pump sprayer, where you mix 2 fluid ounces of concentrate per gallon of water and spray to cover about 500 square feet per gallon. The hose-end is faster for big areas; the tank sprayer gives you more precise control and is better near garden beds where you want to avoid drift.

The best time is when the weeds are young and actively growing, which is typically spring and early fall, on a calm, mild day. Actively growing weeds absorb and move the herbicide most effectively, so a lush, growing dandelion dies far more reliably than a stressed one. Aim for daytime temperatures between 45 and 90 degrees Fahrenheit: below 45 the weeds are not growing, and above 90 you risk stressing your lawn and increasing herbicide drift. Choose a windless day to prevent the spray from drifting onto gardens and ornamentals, and make sure no rain is expected for at least an hour or two, though most products are rainproof within about an hour. Fall spraying is especially effective on perennial broadleaf weeds because they are moving energy to their roots, carrying the herbicide down with it.

A few tough broadleaf weeds are simply harder to kill and often survive a single application. Wild violet, ground ivy (creeping charlie), and oxalis are the usual culprits, because they have waxy leaves or deep, persistent root systems that resist the standard 3-way formula. Other times survival comes down to conditions: spraying weeds that were drought-stressed, dormant, or not actively growing, applying in too much heat or wind, or mowing right before or after, which removes the leaves that absorb the herbicide. The fix is usually to spot-treat the survivors after 2 to 3 weeks, sometimes with a product containing triclopyr, which is stronger on these stubborn species. Just remember to stay within the label limit of 2 broadcast applications per year.