Nutsedge Identification and Control

Nutsedge Control can be difficult, even by professionals.  Understanding more about how it grows will help you understand why it can be such a big problem in your lawn.  If you are a professional, nutsedge may be your biggest battle in your customers lawns.  Knowing that it is one of the biggest weed problems in the whole world doesn’t make it seem any better. It takes a combination of tactics, but you can eliminate sedge from lawns.  It just may take a few years until they are completely clean.

Nutsedge Identification

Nutsedge, also known as just sedge or nutgrass, is a perennial plant from the Cyperaceae family.  It reproduces primarily by small underground tubers, called nutlets, that form at the bottom of underground stems. The underground stems are called rhizomes. These tubers, or "nutlets," are connected by rhizomes and can be found up to 14 inches (35 cm) deep in the soil. Yellow nutsedge thrives in poorly drained soils and is often an indicator of excessive moisture.

There are several ways to identify sedges and distinguish them from grasses. Sedge can be identified by the triangular shape of its stem. You can feel the shape by rolling the stem in your fingertips. Sedge leaves are arranged in groups of three, which also distinguishes it from grasses. The leaves are light green to yellowish, and each leaf has a long, tapered tip.  The yellowish color is usually easy to see in a green lawn as being different. Each leaf also has a prominent midrib, and has a slick, shiny, or waxy appearance.

The plant produces yellow-brown flower spikes and tubers, which are key identification features. Its extensive root system makes it a resilient weed, often regrowing from leftover tubers after removal.

A single nutsedge plant can produce several hundred of these tubers during the summer. In one year, the reproduction from one tuber has the potential to produce 1,900 new plants and 7,000 new tubers. Yellow nutsedge can also spread by rhizomes.  Now you can see why it's so tough to control and why it is spreading across your lawn.   Luckily, individual tubers do not live more than 3 years.

Green Kyllinga  (Kyllinga brevifolia)  looks like sedge but the blades are much thinner, it is a lighter color and it doesn't have the nutlets.  Clean your lawn equipment after working in infested areas to prevent spreading Kyllinga to other parts of the lawn. Kyllinga is often mistaken for nutsedge, they are closely related.
Avoid over-watering, especially in areas prone to waterlogging. Improve soil drainage to create less favorable conditions for Kyllinga. Be vigilant and routinely scout for the weed to tackle new invasions promptly. Aerate the soil to improve drainage and reduce compaction, discouraging Kyllinga which thrives in moist areas. Overseed with competitive grass species to increase turf density. Perform a soil test and correct any nutrient imbalances with fertilizers, as healthy grass can more effectively outcompete Kyllinga. You can control Kyllinga with the same products as nutsedge.  It is easier to kill with chemical products since it doesn't have nutlets, but it does spread faster through a lawn. 

Yellow sedge (Cyperus esculentus) typically features lighter green to yellow-green leaves and produces tubers, while purple sedge (Cyperus rotundus) has darker green to purplish leaves. Identification of Purple Nutsedge (Cyperus rotundus):  Leaves: V-shaped and tapered at the tip, shiny green to dark purple.  Stems are triangular in cross-section but not round. Root system is  fibrous with tubers that are purplish-brown and have a nut-like appearance.

Yellow nutsedge grows in moist habitats and forms dense clusters, crowding out native plants. The plant produces yellow-brown flower spikes and tubers, which are key identification features. Its extensive root system makes it a resilient weed, often regrowing from leftover tubers after removal. Yellow nutsedge is a perennial weed, challenging to control due to its robust underground tuber network that can survive adverse conditions. Its rapid reproduction and ability to outcompete crops make it a persistent issue in lawns.

Affect On Ecosystems and Lawns

Yellow nutsedge, a highly invasive plant, affects ecosystems by outcompeting native species, reducing biodiversity, and altering habitat structures. Its dense growth can dominate wetlands, impacting the local water flow and soil conditions. Chemical herbicides used to manage it can contaminate soil and water, potentially harming non-target organisms and ecosystems.

By changing the native vegetation patterns, yellow nutsedge can disrupt food webs. It provides limited value to wildlife compared to native plants, thereby impacting the availability of resources for insects, birds, and other animals.

Nutsedge Control

The best method for controlling nutsedge is to create a healthy, dense, stand of turfgrass that can compete with weeds. Encourage thick turf stands with proper turf maintenance practices, including fertilization, proper irrigation, and frequent mowing at the proper height.   Sedge is most problematic in turf that is mown too short, and/or areas where soils remain moist from poor drainage or overwatering. Sedge can also be a problem in well-drained areas, especially thin turf but it is less likely and won’t spread as easily.

Trying to eliminate sedge by digging it up is probably a waste of time.  If you kill one shoot, the tuber merely sends up another. For complete control, an herbicide product must translocate down and kill the tuber and all the surrounding nutlets.  This can take several applications done over a year to completely eliminate your sedge issue.

To control yellow and purple sedge, you can use a combination of cultural, mechanical, and chemical measures:

1. Cultural Control:

   - Improve drainage in the affected area, as these weeds prefer moist soils.

   - Maintain a thick, healthy lawn through proper fertilization and mowing to outcompete sedge plants.

   - Plant competitive species in garden beds that can outcompete sedge.

2. Mechanical Control:

   - Regularly remove young sedge plants by hand before they establish tubers.

   - Use a sharp hoe or similar tool to sever the roots below the soil surface, but be aware that this may not be completely effective due to the weed's reproductive structures.

   - Mulch garden areas to suppress new sedge growth, applying a thick layer to inhibit light and weed emergence.

Chemical control can be ineffective as tubers remain viable after herbicide application. Repeat treatments are necessary, increasing costs. Cultural practices can help manage yellow nutsedge, but their success hinges on sustained, integrated efforts.

3. Chemical Control:

   - Apply a selective herbicide labeled for sedges on turfgrass. Examples are products containing halosulfuron, imazosulfuron, sulfentrazone, or mesotrione. Follow the manufacturer's instructions for application rates and timing. There are several good sedge control products like Image, Certainty, and Sedgehammer that can be used. Check the labels and choose the most effective product for the grasses in your area.

- Use pre-emergent herbicides that are labeled for control of nutsedge in your specific turf or planting bed.

   - Non-selective herbicides like glyphosate can be used with caution in ornamental beds but will kill any plants they contact.

   - Multiple applications are often necessary to control nutsedges effectively, as they can regrow from tubers left in the soil. Persistence and consistency in treatment are key, applying herbicides at intervals specified on the label until the sedge is eliminated.

4. Integrated Pest Management (IPM):

  - Combination of methods including cultural, mechanical, and chemical for effective long-term control.

  - Monitoring for early detection and immediate action is crucial. Always follow label instructions for herbicides. Use of biodegradable landscape fabric may also be beneficial. Rotate different modes of chemical action to prevent resistance development.

If you are a professional, you will in most cases treat nutsedge as part of your fertilization and weed control services.  In cases where the lawn is over 10% sedge, you should consider charging a special rate for special sedge control services to cover your extra costs. 

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