Viburnum (Snowball Bush) Dieback: Botryosphaeria Canker

Five 5-year-old snowball viburnums in Wisconsin wilted suddenly after beautiful flowering. Leaves stayed green and plump but branches bent. Pruning revealed brown internal discoloration in some stems. No insects found.

Diagnosis: Botryosphaeria Canker

Internal stem browning and sudden wilting without leaf spots point to this fungal canker. The fungus blocks water and nutrient transport. Viburnums are highly susceptible.

Management

• No cure exists once the main crown is infected.
• Pruning out affected branches may help if caught very early.
• Prevention: water during drought, avoid wounding, maintain vigor.

Replacement with a resistant species is the most realistic long-term solution.