Nutsedge in Lawns: Identification, Control, and Prevention

Nutsedge is one of the most frustrating weeds homeowners encounter. It looks like grass at first glance, but it’s a sedge and once it becomes established, it can be very difficult to remove. Understanding how to identify, manage, and prevent nutsedge is the key to keeping it from taking over your lawn.

Identifying Nutsedge

Nutsedge (most commonly yellow nutsedge Cyperus esculentus and purple nutsedge Cyperus rotundus) is a perennial weed that thrives in warm, moist soils. Key features:

• Triangular stems: Unlike true grasses (which have round or flat stems), nutsedge has a distinct three-sided stem.
• Leaf appearance: Leaves are light green, narrow, and glossy, often standing more upright than grass blades.
• Growth pattern: It grows in clumps that spread aggressively.
• Reproduction: Nutsedge spreads mainly through underground tubers (“nutlets”) and rhizomes, which survive in soil and generate new plants year after year.

Early recognition is important. Small patches are easier to control than widespread infestations.

Controlling Nutsedge

Because nutsedge regenerates from underground tubers, simply pulling it out rarely works and furthermore, any broken pieces left in the soil can regrow.

Cultural practices:

• Improve drainage and reduce overwatering since nutsedge thrives in wet soils.
• Aerate compacted areas and correct low spots where water collects.
• Maintain a dense, vigorous lawn through proper mowing and fertilization to help turf outcompete nutsedge.

Chemical controls:

• Selective post-emergent herbicides labeled for nutsedge are the most reliable option. Common active ingredients include halosulfuron, sulfentrazone, and imazosulfuron.
• Multiple applications are often required because of the weed’s underground storage structures.
• Always follow product label directions carefully for timing, rates, and reapplication intervals.

Glyphosate (a non-selective herbicide) will kill nutsedge but also kills surrounding turf and is not appropriate for spot-treating lawns unless a renovation is warranted.

Preventing Nutsedge

Once nutsedge tubers are established, complete eradication is unlikely in a single season. Prevention focuses on making the lawn less hospitable:

• Avoid overwatering and fix poorly drained areas.
• Mow at the correct height for your turf to maintain density and shade out weed seedlings.
• Fertilize properly to keep turf competitive.
• Aerate and dethatch as needed to improve soil conditions and reduce stress on turf.

By reducing stress and improving lawn vigor, you create an environment where turfgrass outcompetes weeds like nutsedge.

Maintaining a Healthy Lawn

Nutsedge is a symptom of broader lawn problems such as excess moisture, compaction, or thin turf. A healthy lawn is your best defense. Key steps include:

• Watering deeply but infrequently (about 1 inch per week).
• Mowing regularly, never removing more than one-third of the blade.
• Monitoring for problem areas and addressing them before weeds mature.

FAQs

What kills nutsedge in lawns?
Selective herbicides containing halosulfuron, sulfentrazone, or imazosulfuron are designed to control nutsedge in turf without harming grass. Multiple treatments may be needed.

Why does nutsedge keep coming back?
Nutsedge produces underground tubers and rhizomes that persist in soil. Even if the top growth is removed, new shoots can emerge from these storage structures. Long-term management is required.

Will nutsedge go away on its own?
No. Nutsedge spreads aggressively once established and won’t disappear without active management.