Arborvitae “Blue Gray Spiky Balls” Are Normal Seed Cones—Watch for Bagworms

Arborvitae with seed cones

The blue-gray spiky balls on branch tips are immature seed cones—normal for arborvitae. No disease or insect issue.

Real Threat: Bagworms

Watch for bagworm caterpillars (they make spindle-shaped bags). Hand-pick and crush any you see—they can defoliate quickly.

Plant Diseases: Arborvitae Browning: Seiridium Canker from Stress; Pine Tree Yellowing Needles and White Sudsy Substance: Insect Identification; Crabapple Trunk Damage and Dead Top Branches: Borer Suspected; Jasmine Leaf Damage and White Blobs: Grasshoppers/Slugs and Mealybugs; Arborvitae Brown Spots After Neighbor’s Chemical Driveway Treatment: Possible Drift Injury; Plumcot Fruit Oozing Clear Resin: Plum Curculio Beetle Damage; Orange Leaf White Fruiting Bodies: Powdery Mildew Management; Variegated Pittosporum Dieback: Shade, Drainage, and Disease; Arborvitae Sudden Death: Root Disease, Not Drought; Tomato Seedling Spots: Need Photo and Seed Source

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