Botanic Garden >> Gardening > >> Question and Answer >> Plant Diseases

Mondo Grass Yellowing: Pythium Root Rot in Louisiana

Summer-Planted Mondo Grass Declining

Mondo grass planted early summer, grew well, now yellowing and disappearing in Louisiana.

Diagnosis: Pythium Root Rot

Most serious disease, caused by Pythium splendens. Affects dwarf mondo more. Symptoms: tip burn → yellowing/browning → crown separates easily when pulled. Promoted by heavy soils, poor drainage.

Management

Fungicides: Some labeled for drench application to mondo grass.
Topdress with Compost: Improves soil microflora competition.
Improve Drainage: Amend soil, avoid waterlogging.

Note

Soil-borne Pythium is difficult to control; prevention via drainage is key.

Plant Diseases: Mondo Grass vs. Buffalo Grass for Low-Maintenance Coastal Lawn; Yellowing Bahiagrass in Florida: Sandy Soil, Weed & Feed Damage, and Iron Deficiency; St. Augustine Yellowing After Rain? Likely Brown Patch Fungus—Organic Cure; Why Pre-Emergent Herbicides Block Grass Seed Germination and How to Repair the Damage; St. Augustine Grass Yellowing from Pool Backwash: Chlorine Damage Remediation; Dwarf Mondo Grass – Dense Dark Green Clumps; Mondo Grass – Dark Green Grass-Like Clumps; Mondo Grass: A Shade-Loving Groundcover for Borders, Containers, and Rock Gardens; Fescue Yellowing: Missing Fall Fertilizer Applications; Mondo Grass Care: Planting, Propagating, Removing, and Troubleshooting

Garden Articles

Dwarf Mondo Grass – Dense Dark Green Groundcover for Shade

Mondo Grass – Dark Green Grass-Like Evergreen Groundcover

Dwarf Mondo Grass: No Winter Cover Needed

Liriope vs. Mondo Grass: Kissing Cousins

Weed Control in Mondo Grass: Choose the Right Herbicide

Why Dwarf Mondo Grass Seed Is Nearly Impossible for Homeowners to Grow

Speeding Up Mondo Grass Spread with Targeted Fertilization

Plants

Diagnosing Mondo Grass Dieback: Root Rot vs. Leaf Spot

Yellow Patches After Organica Lawn Booster: Aeration Side Effect?

Yellowing New Grass in Wisconsin: Rust Disease and Weak Organic Fertilizer

Yellowing St. Augustine After Liquid Iron: Diagnosis Before Reapplication

Mondo Grass (Ophiopogon japonicus)

Planting and Caring for Dwarf Mondo Grass

Best Ground Cover for Deep Shade: Dwarf Mondo Grass Beats Ivy Every Time