Your garden may look great…until this late-summer sign appears

Late-summer gardens often mask underlying issues that become apparent through specific visual cues. While lush growth may dominate the landscape, circular brown patches or ring-shaped dead zones signal root diseases like summer patch and necrotic ring spot. These fungal infections thrive in stressed lawns, particularly those with poor drainage or overwatering.

Summer patch: Silent root destroyer

This disease attacks grass roots during heatwaves, causing water absorption failure. Symptoms include:

• Circular dead zones expanding outward
• Reddish tinge on outer edges of patches
• Healthy inner grass contrasting with dying perimeters

Kentucky bluegrass and fine fescues are most vulnerable. Prevention requires proper soil aeration and avoiding overwatering.

Necrotic ring spot: Ring-shaped decay

Affecting lawns under 10 years old, this disease creates:

• 6-18 inch wide rings with sunken centers
• Yellow/brown outer edges while inner grass remains green
• Complete center die-off over time

Cool, wet soils and excessive thatch exacerbate the problem. Treatment often requires multiple seasons of targeted fungicides.

Pest infestations accelerate damage

Insects become more active during late summer, leaving distinct signs of feeding activity. Chinch bugs, sod webworms, and billbugs represent three major threats requiring immediate attention.

Chinch bugs: Sun-loving sap suckers

These tiny insects cause:

• Dry, yellow/brown patches worsening in heat
• Easily pulled grass due to root damage
• Visible bugs when parting blades

Control methods include:

• Insecticides applied during peak activity
• Taller grass to reduce sun exposure
• Consistent watering to maintain plant health

Sod webworms: Nocturnal grazers

Moth larvae create:

• Thin, clipped grass resembling mowing patterns
• Silk tunnels near soil surfaces
• Flying moths during daytime lawn activities

Effective management involves:

• Evening insecticide applications
• Raking to disrupt tunnels
• Maintaining healthy grass through proper nutrition

Billbugs: Dual-stage destroyers

Adults and larvae attack different plant parts:

• Brown spots from blade chewing
• Hollow stems due to root larvae
• Sawdust-like debris near crowns

Control requires:

• Spring insecticides for adults
• Summer treatments targeting larvae
• Reseeding damaged areas

Weed proliferation accelerates

Late summer sees aggressive weed growth as plants prepare for seed production. Crabgrass and thistle become particularly problematic, requiring proactive measures to prevent next year’s infestations.

Seed head formation: Silent spreaders

Weeds develop:

• Tall seed stalks in late summer
• Wind-dispersed seeds contaminating soil
• Dormant seeds surviving winter

Prevention strategies include:

• Physical removal before seed maturation
• Pre-emergent herbicides in spring
• Thick grass cover through proper mowing

Soil preparation: Foundation for health

Compacted or poorly drained soils create environments where:

• Root diseases thrive
• Weed roots establish dominance
• Water retention becomes problematic

Improvement methods include:

• Aeration to enhance airflow
• Organic matter additions for drainage
• Proper irrigation schedules

Vegetable diseases intensify

Tomato plants and other vegetables face heightened disease risks as temperatures rise. Early blight and septoria leaf spot represent two major threats requiring immediate intervention.

Early blight: Black-spotted decay

This fungal disease causes:

• Target-shaped black spots on leaves
• Yellowing foliage preceding defoliation
• Reduced fruit production

Management involves:

• Copper-based fungicides
• Pruning infected areas
• Crop rotation to break disease cycles

Septoria leaf spot: Progressive infection

Characterized by:

• Small black dots on lower leaves
• Defoliation moving upward
• Premature plant death

Control methods include:

• Chlorothalonil applications
• Removing infected debris
• Increasing air circulation

Proactive maintenance strategies

Preventing late-summer garden decline requires a combination of monitoring, cultural practices, and targeted interventions. Key approaches include:

Regular inspections

• Daily visual checks for new symptoms
• Tug tests to identify root damage
• Moth monitoring during evening hours

Cultural adjustments

• Proper mowing heights (3-4 inches for most grasses)
• Balanced fertilization avoiding excess nitrogen
• Soil pH testing to optimize nutrient availability

Integrated pest management

• Biological controls like parasitic wasps
• Cultural controls through proper watering
• Chemical controls as last-resort options

Late-summer garden health hinges on recognizing early warning signs and implementing targeted solutions. By addressing root diseases, pest infestations, weed proliferation, and vegetable diseases through proactive measures, gardeners can preserve their landscapes’ vitality into fall. Vigilance remains crucial, as hidden threats often escalate rapidly during this critical period.