Tall Fescue

Circular Patches: The most recognizable symptom is the appearance of roughly circular patches of brown, thinning, or dead grass.

Color Changes: Infected grass blades initially turn a dark purplish-green or water-soaked appearance before fading to a light brown or tan. The affected leaves often remain upright.

“Smoke Ring”: In active patches, especially on closely mown turf like golf greens, a dark gray or purplish-black band, often called a “smoke ring,” may be visible at the perimeter of the diseased area, particularly in the early morning when humidity is high. This “smoke ring” is the actively growing mycelium of the fungus.

Leaf Lesions: On individual leaf blades, especially on tall fescue, small, irregular, tan spots with dark brown borders may be present.

High Temperatures and Humidity: The disease is most active during prolonged periods of high humidity and warm temperatures, typically when daytime temperatures are between 75-85°F and nighttime temperatures remain above 65°F (18°C).

Extended Leaf Wetness: Long periods of leaf wetness, often due to heavy dew, frequent rainfall, excessive irrigation, or poor drainage, create an ideal environment for the fungus to spread.

Excessive Nitrogen Fertility: Over-fertilizing, especially with soluble nitrogen sources in late spring or summer, can lead to lush, tender growth that is more susceptible to the disease.

Poor Air Circulation: Shaded areas, dense thatch layers (buildup of organic debris between the grass blades and soil), and compacted soils can trap moisture and reduce air movement, promoting disease development.

Dull Mower Blades: Mowing with dull blades can wound the grass, making it more vulnerable to infection.

Leaf Lesions: This is the most diagnostic symptom. Initial symptoms are small, water-soaked, brownish spots on the leaf blades. These spots quickly enlarge and become oblong or elongated, often running parallel to the leaf veins. Mature spots typically have a tan to gray center and distinct dark brown or purple margins. They can be depressed in the center.

“Gray Fuzzy” Appearance: Under warm, humid conditions, especially when the leaves are wet, the centers of the lesions may develop a gray, fuzzy growth. This is fungal mycelium and spores being produced.

“Fish-hook” or Twisted Leaves: In cool-season grasses like perennial ryegrass and tall fescue, severely blighted leaves may appear twisted or “fish-hooked” at the tip.

Scorched or Blighted Patches: As the disease progresses, numerous lesions can coalesce, causing entire leaf blades to shrivel and die. From a distance, affected areas can resemble drought stress, appearing thin, scorched, or wilted, with a blue-gray cast. These patches can range from small, irregular spots to large, rapidly expanding areas of dead turf.

Stem and Sheath Lesions: Lesions can also appear on the leaf sheaths (where the leaf attaches to the stem) and even on the stems and seed heads, especially in St. Augustinegrass. These tend to be brown to black.

High Temperatures and Humidity: The disease is most active during periods of warm to hot temperatures, typically between 70-95°F (21-35°C), combined with high humidity.

Extended Leaf Wetness: Prolonged periods of continuous leaf wetness (at least 14 hours are often required for infection) are critical for disease development. This can be caused by:

• Frequent rainfall
• Heavy or prolonged dew
• Improper irrigation
• Poor air circulation
• Shade

Excessive Nitrogen Fertility: Lush, tender turfgrass growth stimulated by high nitrogen applications, particularly quick-release formulations, makes the grass more susceptible to infection.

Newly Established Turf: Newly seeded or sodded turf, especially perennial ryegrass and tall fescue, is often more vulnerable to severe outbreaks.

Stress Factors: Other stresses like soil compaction, dull mower blades (wounding the grass), herbicides, and drought can predispose turf to gray leaf spot.

The name “dollar spot” comes from the characteristic circular patches it forms, which are roughly the size of a silver dollar (1-2 inches in diameter) on closely mown turf like golf greens. On taller turf (e.g., home lawns), these spots can coalesce and expand into larger, irregular patches several inches to a foot or more in diameter.

Small, Sunken Patches: The most noticeable symptom is the appearance of small, circular, sunken patches of bleached or straw-colored turf.

Tan Lesions with Reddish-Brown Borders: Lesions are typically hourglass-shaped or elongated, with a tan or bleached center and a characteristic reddish-brown band or border. The tip of the affected leaf may remain green. The lesion is usually located in the center of the blade and sometimes spreads across the entire width.

White, Cobwebby Mycelium: In the early morning, especially when there’s heavy dew or high humidity, a fine, silvery-white, cobwebby fungal growth (mycelium) may be visible on the infected grass blades within the patches. This is a key diagnostic sign, but it disappears as the dew dries.

Overall Thinning: If left unchecked, the disease can cause significant thinning and overall decline of the turf in affected areas.

Moderate Temperatures: The disease is most active when daytime temperatures are in the range of 60-85°F, especially when followed by cool nights.

Prolonged Leaf Wetness: This is perhaps the most critical factor. Extended periods of continuous leaf wetness (often 10-14 hours or more) from dew, fog, light rain, or improper irrigation create an ideal environment for the fungus to infect.

Low Nitrogen Fertility: Turfgrass that is deficient in nitrogen is significantly more susceptible to dollar spot and suffers more severe damage. Lush, vigorously growing turf is better able to outgrow the disease.

Drought Stress: While prolonged leaf wetness is key for infection, turf that is under drought stress (dry soil conditions) is also more vulnerable to dollar spot.

Poor Air Circulation: Shaded areas or areas with poor air movement can prolong leaf wetness, encouraging disease development.

Dull Mower Blades: Mowing with dull blades can wound the grass, making it easier for the fungus to enter.

There are a few key reasons why your tall fescue struggles in the heat:

Inefficient Energy Production (The “C3” Problem): Think of plants like tiny solar panels, converting sunlight into energy (sugars, or carbohydrates). Tall fescue uses a type of photosynthesis called “C3.” While it’s very efficient in cooler temperatures, it becomes much less so when it’s hot. In high heat, the plant actually starts to lose more energy than it produces, kind of like trying to power a house with a tiny solar panel on a cloudy day. This leads to a carbohydrate deficiency, meaning the grass doesn’t have enough energy to grow, repair itself, or fight off diseases. You might notice the grass looking thin, weak, or generally unwell.

Physical Burning in “Hot Spots”: Just like you wouldn’t want to walk barefoot on hot pavement, your grass can get literally burned in certain areas. This is especially common along curbs, sidewalks, driveways, and foundations. These hard surfaces absorb and radiate a lot of heat, creating mini-ovens that scorch the nearby grass. The affected areas will often look brown and crispy, almost like they’ve been blow-torched.

Not Enough Water, or Too Much Water at the Wrong Time: While it might seem obvious, extreme heat increases how much water your grass needs. If it’s not getting enough, the grass cells shrivel, leading to wilting and browning. On the flip side, constantly wet grass in hot weather can encourage fungal diseases, which further weaken the lawn. Watering heavily (1 – 1 1/2 inches) but infrequently (twice per week) is critical during summer stress periods.

You might notice a variety of symptoms, often starting with a dull, bluish-gray color instead of a vibrant green. The grass blades might curl or fold inward (needle-like), and footprints might stay visible for a long time after you walk across the lawn (a sign of wilting). As the stress worsens, patches will start to turn brown, thin out, and eventually die.

The good news is that there are steps you can take to help your tall fescue lawn survive and even thrive through the summer heat. The key is to reduce stress on the grass as much as possible.

Mow High: Set your mower blade to its highest setting, usually 3 1/2 – 4 inches. Taller grass blades provide more shade to the soil, keeping it cooler and helping to retain moisture. This also encourages deeper root growth, making the grass more resilient.

Mow Only When Needed: When your lawn is stressed, the last thing it needs is more stress from being cut. Mow only when the grass has grown significantly (at least an inch), and avoid mowing during the hottest part of the day. If the grass isn’t growing much, don’t mow at all.

Deep and Infrequent: The goal is to encourage deep root growth. Water deeply enough to soak the soil down to 4 – 6 inches each time you water. This usually means applying about 1 – 1 1/2 inches of water. You can check this by placing a tuna can in your sprinkler’s path and seeing how long it takes to fill up.

Timing is Key: The best time to water is in the early morning, between 4 AM and 8 AM. This allows the water to soak in before the sun gets too intense, minimizing evaporation. Watering in the evening can leave the grass wet overnight, which can promote fungal diseases.

Watch for Signs: Don’t just water on a schedule. Look for signs of wilting (dull color, footprints remaining) and water before the grass turns completely brown.

Limit Foot Traffic: Try to keep people, pets, and vehicles off the lawn as much as possible when it’s stressed. Every step puts pressure on the already weakened grass.

Be Cautious With Fertilizer: When your lawn is under significant heat stress, avoid applying fast-release nitrogen fertilizers, as these can force energy-draining growth and worsen the problem. Instead, focus on providing other essential nutrients like potassium (K), which aids in water regulation and stress tolerance. If a soil test indicates deficiencies in phosphorus (P), addressing those can also support healthier root systems. Consider silicon (Si) amendments for increased cell wall strength and overall resilience. Furthermore, applying compost or other slow-release organic fertilizers can be beneficial. These provide a gentle, steady supply of nutrients, including small amounts of nitrogen, along with improving soil health, which collectively helps the lawn cope with stress without overstimulating growth

Address Weeds (Carefully): Weeds compete with your grass for water and nutrients. If you have a few weeds, hand-pulling them is the best option during heat stress. Avoid using chemical herbicides, as they can also stress the grass in hot conditions.

Improve Air Circulation: If you have areas with poor air circulation (e.g., surrounded by dense shrubs or fences), consider pruning to allow more airflow, which can help cool the grass.

By understanding the causes of heat stress and implementing these management strategies, you can significantly improve your tall fescue lawn’s chances of surviving the summer and bouncing back strong in the fall.

Drought stress is primarily about a lack of available water for the grass plants. Here’s why it happens:

Insufficient Rainfall: This is the most obvious cause. When nature doesn’t provide enough water through rain, your lawn’s water reserves quickly deplete.

Poor Soil Conditions: If your soil is very sandy, water drains through it too quickly, leaving little for the grass roots. If it’s heavily compacted clay, water might run off the surface before it can soak in, or it might hold water too tightly, making it hard for roots to extract. Healthy soil with good organic matter acts like a sponge, holding onto water for longer.

Shallow Roots: If your grass has shallow roots (often due to frequent, light watering), it can’t reach deeper into the soil where there might still be moisture. It becomes much more dependent on surface water, which evaporates quickly.

Competition from Weeds or Other Plants: Weeds are often more aggressive at seeking out and using water, effectively “stealing” it from your desirable turfgrass, especially during dry periods.

The signs of drought stress become increasingly obvious as the grass gets thirstier:

Dull, Bluish-Gray Color: The vibrant green will fade to a muted, often grayish-blue hue. This is one of the first visible signs.

Footprints Remain: When you walk across a well-watered lawn, the grass blades spring back quickly. Under drought stress, the blades are limp and won’t bounce back, so your footprints will remain visible for a longer time. This is often called “foot-printing.”

Curled or Folded Blades: To conserve moisture, grass blades will start to curl or fold lengthwise (needle-like), reducing the surface area exposed to the sun and wind.

Wilting: As the stress intensifies, the grass will visibly droop and wilt.

Browning and Dormancy: Eventually, patches will turn yellow, then straw-colored brown. The grass isn’t necessarily dead at this stage; it often goes into a state of dormancy, a survival mechanism where it shuts down most functions to conserve water. If the drought continues for too long, or the stress is too severe, the grass can die. It is important to note that Tall Fescue is not able to remain in dormancy for long before death.

The key to managing drought stress is to help your lawn conserve and efficiently use whatever water is available, and to encourage a strong, deep root system.

Deep and Infrequent Watering Is Key: This is the golden rule. When you water, do it thoroughly so the water soaks deep into the soil (4 – 6 inches). This encourages roots to grow deeper, making them more resilient during dry spells. Aim for about 1 – 1 1/2 inches of water per application.

How to Measure: The Tuna Can Test: You can measure this by placing a shallow can (like a tuna can) in the area you’re watering and seeing how long it takes to collect 1 inch of water.

Timing is Key: Water in the early morning (between 4 AM and 8 AM). This allows the water to soak in before the sun gets too intense and minimizes water loss from evaporation.

⚠️ Warning⚠️ : Watering in the evening or at night can leave the grass wet overnight, increasing the risk of fungal diseases.

Mow High: Set your mower blade to its highest setting (typically 3 1 2/2 – 4 inches for tall fescue). Taller grass blades shade the soil, reducing water evaporation, and encourage deeper root growth, which helps the plant access more water.

Mow Only When Needed: When grass is stressed by drought, it slows or stops growing. Mowing adds additional stress. If your lawn isn’t growing much, simply don’t mow it. If you must mow, do so when the grass is dry, and avoid removing more than one-third of the blade length.

Reduce Other Stresses
Limit Foot Traffic: Stay off the lawn as much as possible when it’s showing signs of drought stress. The blades are brittle, and traffic can easily break them or compact the soil, making it harder for water to penetrate.

Avoid Improper Fertilization (Especially Fast-Release Nitrogen): As discussed previously, quickly available nitrogen forces the grass to put energy into top growth, which requires more water and drains the plant’s limited resources. This can severely weaken the lawn during drought. If you are going to apply anything, consider potassium (K) which improves the plant’s ability to regulate water, or slow-release organic amendments like compost, which improve soil health and water retention over time.

Manage Weeds: Weeds compete fiercely for water. However herbicides can further stress the grass in hot, dry conditions so we’ll need to be very careful with treatment.

Aerate Compacted Soil (in cooler, moister times): Fescue lawns should be aerated each fall.. This creates holes that allow water and air to penetrate deeper into the root zone, improving the lawn’s ability to handle future droughts.

Mulch Landscape Beds: Mulching around trees and shrubs in nearby landscape beds helps retain soil moisture, benefiting those plants and reducing their competition for water with the lawn.

By proactively managing your tall fescue lawn with these strategies, you can significantly improve its resilience during dry periods, helping it stay greener longer and recover faster once the rains return.

Tall fescue is a non-spreading grass, meaning it will never fill in bare or thin areas on its own. Each summer, it’s normal to lose up to one-third of your lawn’s density to heat stress, and additional losses can occur from disease, improper mowing, drought, insects, or heavy traffic. Because fescue cannot repair itself naturally, yearly seeding is critical to restoring density and maintaining a full lawn.

We pair overseeding with core aeration to relieve soil compaction, strengthen root systems, and significantly improve seed-to-soil contact. We use a premium, weed-free seed blend treated with a root stimulant, water-retention agent, and nutrient package to promote fast, healthy establishment. A fungicide is also applied at seeding to protect vulnerable seedlings from gray leaf spot disease. Results of our seeding service are guaranteed.

Proper watering is essential for success. Newly seeded areas must be watered twice daily for 3–5 weeks to ensure consistent germination and establishment. Skipping or reducing watering during this period will greatly impact results.

DIY seeding is an option, but we strongly recommend avoiding low-quality, weed-contaminated seed commonly sold at big box stores. If seeding yourself, we suggest Aquamaxx (Landscape Supply, Virginia Beach) or Southern Belle (Horizon Distributors, Chesapeake & Suffolk). As with professional seeding, consistent twice-daily watering is required for germination.

Tall fescue is extremely vulnerable to fungal diseases, which are common during hot, humid summer conditions. If disease or insects damage the turf, fescue cannot naturally fill back in. For this reason, preventative treatment is strongly recommended for all fescue lawns. Even with protection, some damage is possible, so proper watering is critical and early signs of disease should be addressed immediately.

Our program provides season-long protection against both fungal diseases and turf-damaging insects. It includes one dedicated insect control application, three fungicide applications paired with a gentle nutrient package to support recovery, and one combination application that delivers insect control, fungicide, and nutrients together. Light nutrient packages are included throughout the summer to spoon-feed the lawn during peak stress periods.

This program protects fescue from common threats such as white grubs and fall armyworms while helping the lawn maintain color, density, and overall health throughout the summer months. It is recommended for all fescue lawns and is designed to keep your lawn looking its best all season long.

DIY treatment is possible using professional-grade products. We recommend Headway G (or a generic equivalent) for disease control, available at professional turf suppliers or online at domyown.com. For insect control, a DIY plan typically includes two applications of Acelepryn G (April and May) and four monthly applications of Headway G from May through August. Always read and carefully follow all label directions when applying these products.