Fescue grass, particularly Tall Fescue (Festuca arundinacea), is a popular choice for many lawns due to its resilience, deep root system, and ability to tolerate shade and drought. However, there are times when fescue becomes an unwanted intruder in a different type of lawn, or perhaps an overzealous patch needs to be managed without harming the surrounding desirable turf. This scenario often presents a significant challenge for homeowners and lawn care professionals alike. The goal is to selectively remove or suppress the fescue while leaving the desired grass species, such as Bermuda, Zoysia, or even a different variety of fescue, unharmed.
Understanding the biology and growth habits of fescue is the first step in developing an effective control strategy. Fescue is a cool-season grass, meaning it thrives in cooler temperatures and can go dormant in extreme heat. Conversely, many warm-season grasses are most active during the summer months. This difference in growth cycles can be leveraged for selective control.
Identifying the Problem Fescue
Before you can eliminate fescue, you need to be certain it’s fescue you’re dealing with. Fescue varieties, especially Tall Fescue, are known for their coarse texture and dark green color. They often form dense clumps and can look quite different from finer-bladed grasses.
Distinguishing Fescue from Other Grasses
The most common grasses homeowners struggle with regarding fescue are often warm-season varieties. Bermuda grass, for example, spreads via rhizomes and stolons, creating a dense, fine-textured carpet. Zoysia grass also spreads aggressively and has a similar texture to Bermuda. Other cool-season grasses like Kentucky Bluegrass have a boat-shaped tip on their blades and a finer texture.
Leaf Blade Characteristics
A key differentiator is the leaf blade itself. Tall Fescue blades are often described as coarse, with a prominent central vein that can be felt by running your fingernail along the blade’s surface. They have a pointed tip. In contrast, Bermuda grass has very fine, narrow leaves. Zoysia grass leaves are also relatively fine but can be a bit wider than Bermuda and have a slightly fuzzy appearance.
Growth Pattern
Fescue is a bunch-type grass, meaning it grows in distinct clumps. While it can spread, it doesn’t typically form the extensive, interconnected network of rhizomes and stolons that characterize aggressive warm-season grasses like Bermuda. This clumping behavior can be an indicator, though over time, dense patches can appear to spread.
Selective Fescue Control Methods
Achieving selective fescue removal without harming other grass types is a nuanced process. It often involves a combination of cultural practices and, in some cases, carefully chosen chemical treatments. Timing is also critical, as exploiting the growth differences between cool-season and warm-season grasses can significantly improve your chances of success.
Cultural Control Strategies
These methods focus on manipulating the growing environment to favor desirable grass species and disadvantage fescue. They are generally more eco-friendly and less likely to cause collateral damage.
Mowing Height Adjustments
The height at which you mow your lawn can have a profound impact on the health and competitiveness of different grass types. For many warm-season grasses, maintaining a slightly higher mowing height can encourage deeper root growth and better shade tolerance.
Fescue, particularly Tall Fescue, can tolerate a wider range of mowing heights. However, if you are trying to suppress fescue in a lawn of finer-bladed grasses, you might consider a slightly lower mowing height for the desirable grasses, provided they can tolerate it. This can stress the fescue by forcing it to expend more energy on blade production rather than root development. Conversely, if you are trying to favor a cool-season grass over an encroaching warm-season grass, you would want to maintain a higher mowing height for the cool-season grass.
Watering Practices
Watering deeply and infrequently is a general rule for a healthy lawn, as it encourages deep root growth. However, tailoring your watering schedule can also be a tool for selective control.
If you are trying to suppress fescue in a warm-season lawn, you might consider allowing the warm-season grass to go into a slight dormancy during the cooler, wetter periods of spring and fall when fescue is actively growing. Conversely, during hot, dry summer months when fescue struggles, providing adequate water to your warm-season lawn will help it outcompete the dormant or stressed fescue.
Fertilization Strategies
The type and timing of fertilization can also influence grass competition. Warm-season grasses typically benefit from nitrogen-rich fertilizers during their active growing season, which is summer. Applying these fertilizers can give your warm-season lawn a competitive edge over fescue, which might be stressed by heat or be entering a less vigorous growth phase.
For cool-season grasses that you want to remain dominant, appropriate fertilization in the fall and spring is crucial. This ensures they have the nutrients they need to thrive and outcompete any encroaching warm-season grasses.
Aeration and Dethatching
These practices improve soil health, air circulation, and water penetration, all of which benefit the overall lawn. When dealing with fescue encroachment, they can help create a more favorable environment for your desired turf.
Aeration helps to alleviate soil compaction, allowing desirable grass roots to penetrate deeper. Dethatching removes the layer of dead organic matter that can build up at the base of grass plants. A thick thatch layer can harbor diseases and prevent water and nutrients from reaching the soil. By managing thatch, you can improve the health of your target grass and potentially weaken the fescue.
Chemical Control Options (Use with Caution)
When cultural methods are not enough, chemical controls may be considered. However, this is where the risk of harming desirable grass is highest. Selective herbicides are designed to target specific types of plants, but they are not always foolproof, especially when dealing with closely related grass species.
Understanding Herbicide Selectivity
Herbicides are categorized by their selectivity. Non-selective herbicides, like glyphosate, will kill all vegetation they come into contact with. Selective herbicides are formulated to target certain plant families or species while leaving others unharmed.
The challenge with fescue control lies in finding herbicides that are selective enough to target fescue without harming other turfgrass species, especially when you have different types of desirable grass in the same lawn.
Selective Herbicides for Fescue Control
There are a limited number of herbicides that can effectively target fescue while sparing other common lawn grasses. This often requires a deep understanding of herbicide chemistry and grass tolerance.
One common approach involves using herbicides that are more effective on cool-season grasses like fescue when applied during the warm season when warm-season grasses are actively growing. Conversely, during cooler seasons, herbicides that target warm-season grasses might be used to suppress fescue.
For example, certain post-emergent herbicides containing active ingredients like quinclorac can be effective against crabgrass and sometimes offer suppression of certain fescue varieties when applied at specific timings and rates. However, their effectiveness on fescue can vary.
Another approach might involve using a pre-emergent herbicide to prevent fescue seed germination, but this is only useful if the fescue is spreading from seed and you are not dealing with established clumps.
It is crucial to always read and follow the product label for any herbicide. The label will specify which grass types the product is safe for, the correct application rates, and the optimal timing for use. Misapplication can lead to significant damage to your lawn.
Spot Treatment for Targeted Removal
When dealing with isolated patches of fescue, spot treatment is often the most practical and least damaging approach. This involves applying a herbicide or other control agent directly to the fescue clump.
If using a non-selective herbicide for spot treatment, such as glyphosate, extreme care must be taken to avoid overspray onto desirable grass. You can use a shield or a brush to apply the herbicide directly to the fescue leaves.
Alternatively, you could consider carefully digging out the fescue clumps and immediately reseeding the area with your desired grass species. This method is labor-intensive but completely avoids the risks associated with herbicides.
Biological and Organic Approaches
For those seeking more environmentally friendly solutions, biological and organic methods can be explored, though they often require more patience and persistence.
Herbicidal Soaps and Natural Oils
Some organic lawn care practitioners use herbicidal soaps or natural oils derived from plants. These can be effective against broadleaf weeds and some grasses, but their selectivity on turfgrass can be highly variable and often results in browning of any grass they touch. Their effectiveness against established fescue can also be limited.
Promoting Healthy Competition
The most effective organic approach is to create an environment where your desirable grass species can outcompete the fescue. This means focusing on all the cultural practices mentioned earlier: proper mowing, watering, fertilization, and soil health. A dense, healthy lawn of the desired grass species will naturally suppress the growth of fescue.
Timing is Everything: Leveraging Growth Cycles
The success of any selective fescue control strategy hinges on understanding and exploiting the different growth cycles of fescue and your desired turfgrass.
Cool-Season vs. Warm-Season Grass Dynamics
Fescue, as a cool-season grass, thrives in spring and fall. During the hot, dry summer months, it may go dormant or become stressed. Warm-season grasses, conversely, are at their peak growth during the summer.
Spring Application Strategies
In early spring, as fescue begins to green up and grow actively, it is often more susceptible to certain herbicides. If you are trying to control fescue in a warm-season lawn that is still dormant or just beginning to emerge, applying a selective herbicide that targets fescue could be an option. However, the risk of phytotoxicity to the emerging warm-season grass must be carefully considered.
Summer Control Tactics
During the peak of summer, when fescue is stressed by heat and drought, it may be more vulnerable. If your desirable grass is a heat-tolerant warm-season variety, this is a good time to ensure it is well-watered and fertilized, allowing it to outcompete the struggling fescue. Non-selective spot treatments can also be applied during this period, as the surrounding desirable grass may be less likely to be negatively impacted if it is actively growing and healthy.
Fall is Crucial for Cool-Season Grasses
Fall is the prime season for cool-season grasses. If your goal is to control fescue within a lawn of a different cool-season grass, fall offers opportunities. However, the selectivity challenge remains.
If you are trying to suppress fescue in a lawn of another cool-season grass, focusing on strengthening your desired grass through proper fall fertilization and cultural practices will be key. This helps your target grass enter winter in a strong, healthy state, better able to compete the following spring.
Strategies for Different Lawn Types
The specific approach you take will depend heavily on what kind of grass you want to keep.
Controlling Fescue in a Warm-Season Lawn
This is a common scenario where homeowners with Bermuda, Zoysia, or Centipede grass find fescue encroaching. The key here is to leverage the seasonal differences.
Summer Advantage
During the hot summer months, your warm-season grass should be actively growing and resilient. Fescue, being a cool-season grass, may struggle with the heat and lack of moisture. This is the ideal time to ensure your warm-season lawn is healthy and robust. Proper watering and fertilization of your warm-season grass will allow it to outcompete the fescue.
Spot treatments with non-selective herbicides can be done during summer when the risk of harming the actively growing warm-season grass is lower, provided care is taken to avoid overspray.
Pre-Emergent Application (Limited Usefulness for Established Fescue)**
While pre-emergent herbicides can prevent fescue seed germination, they are generally not effective against established fescue plants. If fescue is already a problem, you’ll need post-emergent solutions or cultural practices.
Controlling Fescue in a Cool-Season Lawn
This situation can be more complex, as you are dealing with two types of cool-season grasses that have similar growing needs and tolerances.
Identifying the Desired Fescue Variety
If you have different fescue varieties, you’ll need to be even more precise. For instance, if you have fine fescue and Tall Fescue is encroaching, the texture difference will be a key visual cue.
Herbicide Use Requires Extreme Caution
Finding herbicides that can selectively remove one cool-season grass while leaving another unharmed is extremely difficult and often not feasible for the average homeowner. Many herbicides that target fescue will also damage or kill other desirable cool-season grasses.
In this scenario, cultural practices become paramount. Maintaining optimal mowing heights, proper watering, and ensuring good soil health for your desired cool-season grass will be the most effective long-term strategy. Physical removal of fescue clumps by digging them out and reseeding is also a viable, albeit labor-intensive, option.
Prevention is Key: Stopping Fescue Before It Starts
The best way to deal with unwanted fescue is to prevent it from becoming a problem in the first place.
Healthy Lawn Practices for Fescue Prevention
A dense, healthy lawn of your desired grass species is the best defense against fescue encroachment.
Proper Mowing, Watering, and Fertilization
Consistently apply the best practices for your specific turfgrass type. This includes mowing at the correct height for your grass, watering deeply and infrequently, and fertilizing at the appropriate times of year. A strong root system and healthy foliage will make it difficult for fescue seeds to germinate and establish.
Overseeding with Desired Grasses
If you have bare patches or thin areas in your lawn, fescue seeds may find fertile ground to grow. Regularly overseeding your lawn with your desired grass species will help to fill in these areas and create a denser turf that is more resistant to weed invasion, including fescue.
Limiting Fescue Seed Sources
Be mindful of where fescue seeds might be coming from. This could include neighboring properties, contaminated soil brought in for landscaping, or even certain types of mulch.
By implementing these strategies and understanding the specific needs of your lawn, you can effectively manage fescue grass and maintain a beautiful, healthy turf. Remember that patience and persistence are often required, especially when relying on cultural and organic methods. Always consult with local lawn care professionals or your county extension office if you have specific questions or are unsure about the best course of action for your situation.
Why is Fescue Grass Difficult to Control in a Mixed Turf?
Fescue grasses, particularly fine fescues and tall fescues, are known for their dense growth habit and deep root systems, making them resilient and difficult to eradicate without impacting desirable turf species. They can outcompete other grasses for resources like sunlight, water, and nutrients, leading to their dominance in a lawn.
Their genetic makeup often makes them resistant to herbicides that are safe for other common turfgrasses like Kentucky bluegrass or perennial ryegrass. This means standard weed control methods might not be effective or could inadvertently damage the desired turf, necessitating a more nuanced approach to management.
What are the Best Non-Chemical Methods for Fescue Control?
Physical removal is a highly effective, albeit labor-intensive, non-chemical method for controlling fescue. This involves carefully digging out fescue clumps, ensuring that as much of the root system as possible is removed to prevent regrowth. This is particularly effective for isolated patches or when fescue has just begun to invade.
Improving the health and vigor of your desired turfgrass is also crucial. This includes proper mowing height, adequate watering, and appropriate fertilization, which can help the desirable grasses outcompete the fescue. Overseeding with a more aggressive, desirable turf species can also help to dilute and suppress fescue growth over time.
When is the Best Time of Year to Apply Herbicides for Fescue Control?
The optimal time to apply herbicides for fescue control is typically during the active growing season, when the fescue is most susceptible to chemical treatment. This generally falls in the spring and early fall when temperatures are moderate and the grass is actively absorbing nutrients and water.
Applying herbicides when fescue is stressed due to drought or extreme heat can reduce their effectiveness and increase the risk of damage to desirable turfgrasses. Conversely, applying when fescue is dormant will also render most herbicides ineffective, highlighting the importance of timing for successful control.
Are There Specific Herbicides Recommended for Fescue Control?
Yes, certain selective herbicides are designed to target specific grass types, including fescues, while minimizing harm to other lawn grasses. Products containing fenoxaprop-p-ethyl or quinclorac are often recommended for controlling unwanted fescue in other turf species, but it’s crucial to always read and follow label instructions precisely.
These herbicides work by interfering with specific metabolic processes within the fescue plant. However, even selective herbicides can cause temporary discoloration or injury to desirable turf if misapplied. Always perform a small test patch in an inconspicuous area to assess the tolerance of your desired turf before widespread application.
How Can I Prevent Fescue from Re-establishing After Removal?
Preventing re-establishment involves maintaining a healthy and dense desirable turf. This includes regular aeration to improve soil structure and drainage, overseeding with robust turf varieties to fill in any bare spots quickly, and proper fertilization to encourage vigorous growth.
Furthermore, prompt removal of any new fescue seedlings that appear is essential. Early detection and removal, either manually or with targeted spot treatments, can prevent small invasions from becoming established infestations, thus safeguarding your lawn’s composition.
What are the Risks of Using Non-Selective Herbicides for Fescue Control?
The primary risk of using non-selective herbicides, such as glyphosate, is that they will kill all vegetation they come into contact with, including your desired turfgrass. This can lead to large bare patches in your lawn that are then susceptible to weed invasion and erosion.
While effective for complete removal, these products require extreme care and precision in application. Spot treatments must be applied with a shield or targeted sprayer to avoid drift onto surrounding desirable grass. If a broad application is necessary, it’s usually followed by complete lawn renovation.
How Can I Improve the Health of My Desired Turfgrass to Outcompete Fescue?
Enhancing the health of your desired turfgrass involves implementing a comprehensive lawn care program tailored to its specific needs. This includes proper mowing heights, ensuring you don’t cut too short as this stresses the grass and makes it vulnerable. Regular watering, providing about 1-1.5 inches of water per week, ideally in the early morning, is also critical.
A balanced fertilization schedule, based on soil test results, will provide the necessary nutrients for strong root and shoot development. Aeration, at least once a year, helps to alleviate soil compaction, improving air and water penetration to the roots, which further strengthens the desirable turf against competition from fescue.