Does Crossbow Herbicide Kill Grass?

The Short Version

• Crossbow does not kill mature grass: This weed killer is designed to spare grass while clearing away broadleaf weeds, brush, and woody vines.
• Tender or sensitive lawns can burn: Newly seeded yards, drought-stressed turf, and specific grass types like St. Augustinegrass can suffer serious chemical injury.
• Clover will die: The spray targets broadleaf plants, so white or red clover mixed into your lawn will die along with the unwanted weeds.
• Application conditions matter: Spraying in weather above 85 degrees Fahrenheit or mixing the product too strong can scorch even hardy lawn grasses.

How Crossbow Targets Weeds Without Harming Mature Grass

Crossbow is a selective herbicide, which is a weed killer designed to spare grass while destroying unwanted plants. It uses two active chemical ingredients named triclopyr and 2,4-D. Both ingredients mimic natural plant hormones, causing rapid and uneven cellular growth in target weeds. The treated plants twist, curl, and collapse within a few days because they cannot support their own runaway growth.

True grasses have a completely different internal biology than broadleaf weeds. Mature grass blades process and break down these hormone-mimicking chemicals without suffering cell wall collapse. Because of that natural defense mechanism, an established turf, which is a mature, well-rooted lawn, stays healthy and green while nearby weeds wither.

Broadleaf weeds include flowering plants like dandelions, wild blackberries, creeping Charlie, thistle, and clover. If you enjoy having clover in your yard for natural nitrogen or green cover, remember that Crossbow considers clover a target weed. The chemical cannot distinguish between an unwanted patch of poison ivy and desirable lawn clover.

The liquid solution absorbs straight through the foliage and travels through the plant stems down into the root system. That deep root action makes the spray effective against deep-rooted woody brush and persistent brier patches. As long as your lawn grasses are fully grown and healthy, they simply ignore the hormone disruption that clears out the weeds.

Grasses That Tolerate Crossbow vs. Sensitive Turf Types

Different grass species react to brush killers in very different ways. Most cool-season northern lawn grasses tolerate standard applications of Crossbow without signs of damage. Kentucky bluegrass, perennial ryegrass, and tall fescue easily handle label-recommended rates once their roots are fully established.

Pasture grasses also demonstrate strong tolerance against this herbicide. Species such as orchardgrass, timothy, smooth brome, and tall fescue handle regular pasture sprays, which is why farmers use it around grazing land. Common warm-season pasture and lawn grasses like established Bermudagrass and bahiagrass also show good tolerance during their active summer growing season.

Sensitive grass species can suffer severe leaf burn, yellowing, or permanent die-off when sprayed. Warm-season varieties such as St. Augustinegrass, centipedegrass, and carpetgrass absorb the chemical too quickly and cannot metabolize it safely. Spreading this product across a St. Augustine lawn often leaves large dead spots that take months to recover.

Bentgrass and dichondra also show extreme sensitivity to these active ingredients. If you have an ornamental putting green or a specialty ground cover, keep this spray completely away from those areas. Always confirm your exact lawn species before mixing a tank, especially if you live in a southern region with warm-season turf.

Common Mistakes That Cause Lawn Damage

Spraying during high summer heat is the fastest way to turn a green lawn brown. When air temperatures rise above 85 degrees Fahrenheit, the chemical compound begins to vaporize off the leaves. This chemical vapor scorches surrounding grass blades and creates chemical fumes that can injure nearby ornamental shrubs.

Applying the spray to young seedlings will also ruin a lawn renovation. Young grass seedlings have thin leaves, tender shoots, and tiny root systems that cannot filter out heavy herbicide compounds. If you spray before new grass has gone through at least three regular mowings, the chemical will stunt or kill the young turf.

Mixing the chemical too strong will overwhelm even the toughest lawn varieties. Some people assume adding an extra splash of concentrate will kill tough briers faster, but excessive strength burns grass leaves on contact. Puddling the spray so it drenches the soil also forces grass roots to pull in concentrated chemical that burns the plant from below.

Spraying a thirsty, heat-stressed lawn causes unnecessary turf injury. Grass that has gone dormant or weak from prolonged drought lacks the energy needed to process chemical exposure. Make sure your lawn receives adequate moisture and is actively growing before you treat any weeds.

How to Spot-Spray Weeds Safely

Spot-spraying individual weed patches protects the surrounding lawn much better than treating the entire yard at once. Taking a deliberate approach keeps the liquid on target foliage and off sensitive grass blades.

1. Check the weather forecast: Pick a clear day with calm winds below five miles per hour. Make sure daytime temperatures will stay between 55 and 80 degrees Fahrenheit for the next 24 hours, with zero rain in the immediate forecast.
2. Put on protective gear: Wear chemical-resistant rubber gloves, eye goggles, long sleeves, durable long pants, and waterproof boots. Keep pets and children inside the house while you mix and spray.
3. Measure and mix accurately: Fill your tank sprayer halfway with clean water before adding chemical. Measure the exact amount of herbicide listed on the product container for spot treatments, pour it in, and add the rest of the water. Swirl the tank gently so the chemical blends evenly with the water.
4. Adjust your sprayer nozzle: Turn the nozzle tip so it produces a coarse spray with medium droplets rather than a fine fog. A fine mist creates drift, which is spray mist carried by the wind onto healthy grass, vegetable gardens, or prized flowerbeds.
5. Coat the weed leaves lightly: Hold the wand twelve to eighteen inches above the target weed. Press the trigger just long enough to wet the leaves until damp, stopping before the liquid drips off into the surrounding soil.
6. Rinse your sprayer in a safe location: Triple-rinse the empty sprayer tank with clean water. Spray the rinse water out over a weed-choked fence line away from tree roots, garden beds, and street gutters. Never dump chemical rinse water down household drains or onto hard pavement.

Reseeding Timelines and Yard Safety

Planning your lawn care schedule helps you avoid planting grass seed into chemically treated soil. The active ingredients linger in the top layer of dirt for several weeks while sunlight and natural soil bacteria break them down. If you scatter grass seed too soon after spraying, the residual chemical prevents new seeds from germinating.

Wait at least three to four weeks after your last spray application before sowing new grass seed. If your yard experienced cold weather or little rainfall after spraying, wait five or six weeks to be safe. Soaking the soil with a garden sprinkler during that waiting period helps reactivate soil microbes and speeds up natural chemical breakdown.

Keep family members and outdoor pets off treated lawn areas until the liquid has dried completely. On a warm day with a light breeze, the grass blades generally dry within two to four hours. Once dry, the active ingredients bind firmly to the plant tissue and will not transfer onto shoes, bare feet, or dog paws.

Keep your spray wand well outside the drip line of valuable yard trees and decorative garden beds. Tree roots reach out horizontally beneath your lawn and can pull herbicide straight from the soil into their canopy. If spray accidentally hits a prized garden shrub or tomato plant, rinse the foliage with a garden hose within five minutes to wash the residue off before it absorbs.

FAQs

Does Crossbow kill clover mixed into a lawn?

Yes, Crossbow kills all types of clover growing in a lawn. Clover is a broadleaf plant, which is the exact plant family this brush killer is formulated to eliminate. If you want to maintain a mixed clover lawn, avoid spraying this chemical across those sections of your yard.

How long does Crossbow stay active in the ground?

The active chemical ingredients typically break down in the soil within 30 to 45 days. Warm soil temperatures, adequate moisture, and active soil microbes break the compounds down naturally over several weeks. In dry or cold soil, that natural breakdown slows down, meaning chemical residues can linger longer.

Can you spray Crossbow on a brand-new lawn?

No, you should never apply Crossbow to newly sprouted grass seedlings. Baby grass blades are tender and absorb chemical compounds that mature grass easily ignores. Wait until your new lawn has been mowed at least three times before applying any selective brush killer.

What should you do if Crossbow drifts onto valuable garden plants?

Rinse the affected plants with fresh water from a garden hose right away. You must wash the spray off the foliage within minutes before the plant leaves absorb the chemical. If the plant shows leaf curling a day later, prune off the damaged branch tips and keep the plant well-watered.