Shrubs are a vital part of your landscape, adding beauty, shade, and structure to your yard. But just like your lawn, shrubs are vulnerable to diseases that can weaken or kill them. If left untreated, fungal infections, bacterial diseases, and pest infestations can quickly spread, damaging your entire landscape.
If your shrubs are showing signs of yellowing leaves, spots, wilting, or unusual growths, you may be dealing with a disease issue. Understanding the common shrub diseases in Houston and how to treat and prevent them will help keep your landscape healthy and thriving.
Top Common Shrub Diseases in Houston
Powdery Mildew
Signs: White, powdery fungus on leaves, stems, and buds.
Causes: High humidity, poor air circulation, and damp conditions.
Treatment: Apply a fungicide and prune infected areas to improve airflow.
Leaf Spot Diseases (Fungal & Bacterial)
Signs: Small brown, black, or yellow spots on leaves that grow over time.
Causes: Excess moisture, poor drainage, or infected debris.
Treatment: Remove affected leaves and apply a fungicide to prevent spread.
Root Rot (Phytophthora & Other Fungal Infections
Signs: Yellowing leaves, slow growth, and wilting despite proper watering.
Causes: Overwatering, poor drainage, and compacted soil.
Treatment: Improve soil drainage, avoid overwatering, and apply a soil fungicide if necessary.
Rust Disease
Signs: Orange, yellow, or brown powdery spots on the underside of leaves.
Causes: Wet, humid conditions and overcrowded plants.
Treatment: Prune affected leaves and apply a fungicide to control the spread.
Fire Blight
Signs: Blackened, wilted branches that appear “burned” and curled leaves.
Causes: Bacterial infection that spreads through rain and insects.
Treatment: Prune infected branches and apply a copper-based fungicide during the dormant season.
Canker Disease
Signs: Sunken, discolored, or cracked areas on stems and branches.
Causes: Fungal infection that enters through wounds or weakened plants.
Treatment: Prune infected branches and disinfect tools to prevent spread.
Anthracnose
Signs: Brown, irregular leaf blotches that lead to defoliation.
Causes: Cool, wet spring weather and fungal spores in plant debris.
Treatment: Remove affected leaves and apply a fungicide to affected shrubs.
How to Treat Shrub Diseases Effectively
If you suspect your shrubs have a disease, early action is key to preventing further damage. Follow these steps to treat infections:
Identify the Problem
- Check leaves, stems, and roots for discoloration, spots, wilting, or unusual growths.
- Compare symptoms with the common shrub diseases listed above.
- If unsure, consult a professional shrub care expert for diagnosis.
Remove Infected Areas
- Prune infected leaves, stems, and branches using sterilized pruning shears.
- Dispose of affected plant material away from your yard to prevent reinfection.
- Avoid excessive pruning—removing too much foliage can weaken the plant.
Improve Growing Conditions
- Ensure proper drainage to prevent root rot and fungal growth.
- Avoid overhead watering—use drip irrigation or water at the base of plants.
- Space out plants to improve air circulation and reduce humidity buildup.
Apply Disease Treatments
- Use a fungicide or bactericide based on the type of infection.
- For organic options, neem oil or copper-based fungicides can help prevent disease spread.
- Apply treatments in cool, dry conditions to ensure maximum effectiveness.
How to Prevent Shrub Diseases
Prevention is the best defense against shrub diseases. Follow these proactive steps to keep your shrubs disease-free:
Choose Disease-Resistant Shrubs – Select plants that naturally resist common diseases in Houston.
Mulch Properly – Use mulch to retain moisture while keeping leaves dry and reducing soil splash.
Fertilize Regularly – Strengthen plant immunity with a balanced fertilizer to encourage healthy growth.
Water Wisely – Water deeply but infrequently to prevent excess moisture buildup.
Prune Strategically – Trim shrubs in the right season to promote airflow and remove weak branches.
Keep Your Yard Clean – Remove fallen leaves and debris to eliminate potential breeding grounds for diseases.
When to Call a Professional for Shrub Disease Treatment
If your shrubs show severe signs of infection, such as widespread wilting, blackened branches, or rapid leaf loss, professional intervention may be needed. Pest Frog’s shrub care experts can:
Diagnose the disease and determine the best treatment.
Apply targeted fungicides or bactericides to stop the spread.
Provide preventative care to ensure long-term shrub health.
Keep Your Shrubs Healthy Year-Round
A thriving landscape starts with healthy shrubs. Whether you need disease treatment, preventative care, or regular fertilization, Pest Frog’s expert lawn and shrub care services ensure your plants stay strong and beautiful year-round.
📞 Call today for a free shrub health evaluation!