Weed Control in Zoysiagrass: Strategies, Herbicides, and Specific Weed Solutions

Three-Method Weed Management

1. Healthy Lawn: Proper fertilization, watering, mowing = dense turf that resists weeds.
2. Mechanical: Frequent mowing at correct height; hand-pull annuals.
3. Chemical: Herbicides at right time for specific weeds; always read label.

Weed Types

• Broadleaf: Chickweed, henbit, dandelion, spurge, wild onion.
• Grassy: Annual bluegrass, crabgrass, dallisgrass, bahiagrass.

Pre-Emergent Timing

• Summer weeds (crabgrass): spring after 4 days of 60°F nights (forsythia bloom).
• Winter weeds (annual bluegrass): early October.
• Water in after application.

Post-Emergent Use

Specific products for grassy vs. broadleaf weeds when actively growing in early summer. Identify weed first; verify product safety for zoysiagrass; never exceed label rates.

Moss Management

Moss grows where zoysia can't (shade/wet). Fix environment: improve drainage, increase light. Lime/moss killers are temporary.

Avoid "Weed 'n' Feed"

Wrong timing: zoysia fertilized during/after green-up; pre-emergents before green-up.

Specific Weed Solutions

• Annual bluegrass: Pre-emergent mid-September; spring spot-treat with non-selective herbicide before seeding.
• Chickweed: Pre-emergent (isoxaben) or broadleaf herbicides (2,4-D + MCPP). Safe on non-dormant grass; wait 4 mowings on new fescue.
• Wild onions: Two spring sprays at 6-week intervals (non-selective or broadleaf), two fall sprays at emergence. Imazaquin (Image) works. Avoid green-up and new plantings.
• Nutsedge + crabgrass: Mix imazaquin (Image) + MSMA (Crab-E-Rad); 3 applications 10 days apart. Water thoroughly 2 days after to reduce zoysia discoloration.
• Wild violets: Manage population: broadleaf herbicides 3× at monthly intervals. Avoid drought and green-up periods.

Pre-Emergent & New Sod

Q: Will pre-emergent hurt newly laid sod roots?
A: No. Pre-emergent creates surface barrier against seeds. Sod roots establish below it. Keep sod watered.

Imazaquin (Image) Use Notes

Safe on zoysia and centipede; NOT on fescue (severe damage). Follow label: max every 6 weeks.