There are small cone-like bags hanging from my evergreen. What are they?

Those 1-2 inch spindle-shaped "bags" covered in bits of foliage are bagworms (Thyridopteryx ephemeraeformis) — caterpillars that build a protective case from the host plant's own needles or leaves. They're especially destructive on arborvitae, junipers, and spruce, and a heavy infestation can kill an evergreen.

Why they're easy to miss:

• The bags are perfectly camouflaged to look like cones or bits of the plant
• By the time you notice browning, the larvae may have already done significant feeding
• Evergreens often cannot regrow from bare branches the way deciduous trees can, so damage is permanent

Control options:

1. Handpick and destroy bags in fall and winter — each female bag contains 500-1000 overwintering eggs. This is highly effective on small plantings.
2. Bt (Bacillus thuringiensis) or spinosad sprays work well, but only on young larvae (late spring to early summer, roughly when bags are small). Mature larvae in tough bags are hard to kill.
3. Time treatment for June in most of the Midwest/Northeast, when eggs have hatched and larvae are small and feeding.

Monitor susceptible evergreens annually — bagworms come back to the same plants. See Common Tree Pests for more.