By mid-September, Frankfort, KY homeowners start spotting spindle-shaped bags hanging off arborvitae, Leyland cypress, and junipers — that’s bagworm, and unlike the fall webworm on your walnuts and hackberries, this one targets evergreens and can do real damage if it’s the second or third year in a row.
Do Bagworms Kill Arborvitae and Leyland Cypress Trees?
No — a healthy, established arborvitae or Leyland cypress usually survives one season of bagworm feeding, though repeat years or young plantings can suffer real dieback.
Evergreens don’t push a second flush of foliage the way hardwoods do, so a badly defoliated branch on a spruce or arborvitae can stay bare instead of releafing. The University of Kentucky Department of Entomology notes each overwintering bag can hold 500–1,000 eggs, so an untreated infestation compounds fast — a shrub with a handful of bags this year can be stripped within two or three seasons. Young or recently transplanted plants, and mature trees already stressed by drought or root damage, are the ones we see actually die back from it.
Is It Too Late to Treat Bagworms in September, or Do You Have to Remove Them by Hand?
By September spraying no longer works on finished bags — hand removal before bags open next spring is the only fix that actually works now.
Once the caterpillar seals itself inside its bag for the winter, the silk sheds contact insecticides the same way it does on a fall webworm nest, so spraying now is money wasted. Picking bags by hand off a shrub or small tree and dropping them in soapy water or the trash is free and effective — the trouble is scale: a mature Leyland cypress hedge or a specimen tree too tall to reach safely from a ladder is a $75–$200 visit, the same range as a standard trimming and pruning call, since it’s the same climber-and-pole-saw crew working branch by branch. If you’re not sure whether what’s on your evergreen is a bagworm bag or a disease symptom, our tree disease diagnosis page covers how we tell the two apart before any work starts.
Are bagworms and fall webworms the same pest?
No. Bagworms attack evergreens like arborvitae, juniper, and spruce and build spindle-shaped cocoon bags; fall webworms attack hardwoods like walnut and hackberry and build loose silk web tents.
Can I just cut the bags off myself?
Yes, on a small shrub you can reach safely — hand-pick the bags into a bag or bucket and dispose of them, since each one holds hundreds of eggs for next year.
When is the right time to spray for bagworms next year?
Mid-May to early June, while the caterpillars are still small and before they build the bag that shields them from contact sprays.
Not sure if what’s on your evergreen is bagworm, a disease, or something else? Get a free estimate or call or text (859) 310-1209.
Related: Tree Disease Diagnosis Frankfort KY | Tree Trimming & Pruning | Fall Webworms Guide
Source: University of Kentucky Department of Entomology, ENTfact-440: Bagworms on Landscape Plants.
Last updated: September 13, 2026