Bagworms

Signs & symptoms

• Small (1–2") spindle-shaped bags covered in bits of the host plant's needles
• Bags that look like little pinecones or ornaments hanging from the branches
• Browning and thinning of evergreen foliage where they've been feeding
• Bare, dead patches on arborvitae and spruce by late summer

Bagworms are easy to miss because their bags are camouflaged with the plant's own foliage — people often think they're seeing seed cones until the browning starts. On evergreens like arborvitae and spruce, a heavy infestation can strip and kill sections of the plant, and evergreens don't always grow that foliage back.

Because they're protected inside those bags, timing and approach matter. Hand-picking the bags off in fall and winter removes next year's eggs before they hatch.

What to do

• Pick the bags off by hand over fall and winter — each one holds hundreds of eggs
• Watch evergreen privacy hedges closely; bagworms can open up bare spots that don't fill back in
• If a screen of arborvitae is browning out, we can assess what's salvageable and clear what's dead

This is general guidance from three decades of tree work across the Philadelphia area — not a formal diagnosis. When it matters, we'll come look at the actual tree and give you a straight answer, free.

Trees we see this on

Other tree problems