How Do You Kill Dallisgrass Without Killing Grass

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How do you kill dallisgrass without killing grass? This common lawn weed can be a nuisance, but it doesn’t have to take over your yard. Read on to learn how to control dallisgrass and keep your lawn looking its best.

Dallisgrass is a warm-season grass that is native to the southeastern United States. It is a perennial weed that can quickly spread and form dense mats, crowding out desirable grass species. Dallisgrass has several characteristics that make it difficult to control, including its ability to tolerate drought, heat, and poor soil conditions.

Understanding the Nature of Dallisgrass

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Dallisgrass, a warm-season perennial grass, is a common sight in lawns and landscapes across the United States. It is known for its aggressive growth habit and ability to quickly spread, making it a challenging weed to control.Unlike other grass species, dallisgrass has a unique appearance.

Its leaves are wide and have a bluish-green color. The stems are coarse and can grow up to 3 feet tall. Dallisgrass also produces seedheads that are arranged in a distinctive fan-shaped pattern.Dallisgrass is a highly adaptable plant that can thrive in a wide range of soil conditions.

It prefers moist, well-drained soils but can also tolerate drought conditions. This adaptability makes it a difficult weed to control, as it can quickly establish itself in even the most challenging environments.

Growth Patterns

Dallisgrass is a vigorous grower that can quickly spread through both stolons and rhizomes. Stolons are above-ground stems that grow horizontally and produce new plants at their nodes. Rhizomes are underground stems that grow horizontally and produce new plants at their tips.

This aggressive growth habit allows dallisgrass to quickly form dense stands that can crowd out other plants.

Risks and Problems

Dallisgrass infestations can pose a number of risks and problems for lawns and landscapes. The dense stands of dallisgrass can crowd out desirable grasses and other plants, reducing their growth and overall health. Dallisgrass can also produce large amounts of seed, which can spread the infestation to new areas.

In addition, dallisgrass can be a host for a number of pests and diseases, which can further damage lawns and landscapes.

Selective Herbicides for Dallisgrass Control

How do you kill dallisgrass without killing grass

Selective herbicides provide a targeted approach to dallisgrass control, minimizing harm to desirable grasses. Understanding their mechanisms of action and application methods is crucial for effective management.

Types of Selective Herbicides

Several selective herbicides are effective against dallisgrass, each with unique properties:

  • Poast: A post-emergent herbicide that targets dallisgrass while sparing most other grasses. It inhibits lipid synthesis, leading to plant death.
  • Fusilade II: Another post-emergent herbicide that selectively controls dallisgrass. It disrupts cell division, causing growth inhibition and eventual plant demise.
  • Clethodim: A contact herbicide that kills dallisgrass upon direct contact. It damages plant tissues, leading to rapid desiccation and death.
  • Sethoxydim: Similar to clethodim, sethoxydim is a contact herbicide that effectively controls dallisgrass. It disrupts photosynthesis, causing plant starvation and death.

Comparison of Herbicides

The following table summarizes the pros and cons of different selective herbicides for dallisgrass control:

HerbicideMechanism of ActionProsCons
PoastLipid synthesis inhibition– Selective to dallisgrass

Post-emergent application

Systemic translocation

– Can damage desirable grasses if applied at high rates

May require multiple applications

Fusilade IICell division disruption– Highly selective to dallisgrass

Post-emergent application

Systemic translocation

– May not be effective on heavily infested areas

Can cause temporary yellowing of desirable grasses

ClethodimContact herbicide– Fast-acting

Effective on young dallisgrass

– Non-selective, can damage desirable grasses

Requires precise application to avoid drift

SethoxydimContact herbicide– Fast-acting

Effective on young dallisgrass

– Non-selective, can damage desirable grasses

Requires precise application to avoid drift

Cultural Practices to Suppress Dallisgrass

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Cultural practices play a significant role in managing dallisgrass by creating an environment less conducive to its growth. Proper mowing, fertilization, and irrigation techniques can weaken dallisgrass, allowing desirable turfgrasses to thrive.

Adjusting these practices based on lawn type and climate is crucial for effective control. Warm-season grasses, such as Bermuda and Zoysia, tolerate higher mowing heights and require less frequent watering compared to cool-season grasses like Kentucky bluegrass and perennial ryegrass.


Mowing at a higher height promotes a dense turf canopy that shades out dallisgrass seedlings. For warm-season grasses, maintain a mowing height of 2.5-3 inches, while cool-season grasses should be mowed at 1.5-2.5 inches.

Avoid scalping or mowing too low, as this stresses the grass and creates an opportunity for dallisgrass to invade.


Fertilizing the lawn regularly with a balanced fertilizer helps maintain a healthy turf. Nitrogen is an essential nutrient for grass growth, but excessive nitrogen can promote dallisgrass. Use a fertilizer with a slow-release nitrogen source to provide a steady supply of nutrients.

Avoid over-fertilizing, especially during hot, humid weather, as this can weaken the grass and make it more susceptible to dallisgrass invasion.


Proper watering practices can also help suppress dallisgrass. Water the lawn deeply and infrequently to encourage deep root growth. Avoid shallow, frequent watering, which promotes shallow roots and favors dallisgrass.

During periods of drought or high heat, water the lawn more frequently to prevent stress and maintain a healthy turf.

Natural and Organic Control Methods: How Do You Kill Dallisgrass Without Killing Grass

How do you kill dallisgrass without killing grass

Harnessing natural and organic remedies can be an eco-friendly approach to managing dallisgrass. While not as potent as chemical herbicides, these methods offer a gentler touch on the environment and may be suitable for small-scale infestations or organic gardening practices.


Vinegar’s acetic acid content can burn and dehydrate dallisgrass leaves, leading to their eventual death. Mix equal parts white vinegar and water in a spray bottle and apply directly to the grass, avoiding contact with desirable plants. Repeat applications every few days until the grass shows signs of decline.

Baking Soda, How do you kill dallisgrass without killing grass

Baking soda’s alkaline properties can alter the soil pH, making it less favorable for dallisgrass growth. Sprinkle baking soda around the base of dallisgrass plants and water it in. Be cautious not to apply too much, as it can raise soil pH excessively and harm other plants.

Corn Gluten Meal

Corn gluten meal is a pre-emergent herbicide that prevents dallisgrass seeds from germinating. Apply it to the soil before crabgrass germinates in the spring. Corn gluten meal is also a slow-release nitrogen fertilizer, providing additional benefits to the lawn.

Integrated Pest Management for Dallisgrass

Integrated Pest Management (IPM) is a holistic approach that combines multiple methods to manage pests effectively while minimizing environmental impact. For dallisgrass control, IPM involves a combination of cultural practices, selective herbicides, and natural or organic methods.Implementing an IPM program involves the following steps:

Identify the Problem

Correctly identify dallisgrass and assess its severity. Determine the extent of the infestation and the impact on desirable grass species.

Establish Thresholds

Set thresholds for dallisgrass density or coverage that warrant control measures. This helps prioritize management efforts and avoid unnecessary treatments.

Monitor and Evaluate

Regularly monitor dallisgrass populations to track their growth and spread. Evaluate the effectiveness of control measures and make adjustments as needed.

Implement Control Measures

Use a combination of methods to control dallisgrass, including:

  • -*Cultural Practices

    Improve lawn health through proper mowing, watering, and fertilization. Encourage the growth of desirable grass species to outcompete dallisgrass.

  • -*Selective Herbicides

    Apply selective herbicides specifically targeting dallisgrass while minimizing harm to desirable grass species. Follow application instructions carefully.

  • -*Natural or Organic Methods

    Use natural or organic methods such as mulching, hand-pulling, or introducing beneficial insects to suppress dallisgrass growth.

Integrate Methods

Combine multiple methods to maximize effectiveness and minimize the risk of resistance. For example, cultural practices can reduce dallisgrass density, making herbicide treatments more effective.

Adaptive Management

Continuously monitor and evaluate the effectiveness of IPM strategies and make adjustments as needed. This adaptive approach ensures optimal dallisgrass control while preserving desirable grass species.

Prevention of Dallisgrass Infestation

Preventing dallisgrass infestation is crucial for maintaining a healthy lawn. Identifying potential sources and implementing proactive measures can effectively minimize the risk of this invasive weed.

Contaminated Seeds

Avoid using contaminated seeds for lawn establishment or overseeding. Purchase high-quality seeds from reputable suppliers who prioritize weed control and seed purity.

Lawn Clippings

Dallisgrass can spread through lawn clippings. Dispose of clippings properly by composting them or discarding them in sealed bags. Avoid spreading clippings from infested areas to other parts of the lawn.


Overwatering creates favorable conditions for dallisgrass growth. Water your lawn deeply and infrequently to encourage deep root growth and discourage shallow-rooted weeds like dallisgrass.

Maintaining a Healthy Lawn

A healthy lawn with dense turfgrass can resist dallisgrass invasion. Regular mowing, fertilization, and aeration promote a thick and competitive grass cover that makes it difficult for dallisgrass to establish.