Spotted Lanternfly inWashington County, MNSPOTTED LANTERNFLY GUIDE
Washington County occupies the eastern edge of the Twin Cities metro and shares a border with Wisconsin — a state where spotted lanternfly has been detected in recent years. This geographic position makes Washington County one of Minnesota's most vulnerable counties to SLF introduction from the east. Woodbury, Cottage Grove, and Stillwater all sit along the St. Croix River corridor and major highways connecting to Wisconsin, while Lake Elmo and Hugo are growing suburban communities with increasing freight and nursery trade. The Minnesota Dept of Agriculture has placed Washington County in a 2025 watch zone and is working closely with Wisconsin agriculture officials to coordinate border-area surveillance as SLF populations in western Wisconsin expand.
Highest activity zones
SLF Hotspots in Washington County, MN
Woodbury
Active zone
Cottage Grove
Active zone
Stillwater
Active zone
Lake Elmo
Active zone
Hugo
Active zone
Primary SLF food source
Tree of Heaven in Washington County, MN
Tree of Heaven is present in Washington County along the St. Croix River valley, particularly near Stillwater and Afton, as well as along railroad corridors and disturbed roadsides in Cottage Grove and Woodbury. The St. Croix River banks are a known ToH establishment zone and represent a priority surveillance corridor for early SLF detection. MDA is conducting targeted surveys at ToH locations near the Wisconsin border to provide the earliest possible warning of any SLF introduction.
Identify Tree of Heaven →Local action resources
What To Do in Washington County, MN
Report a Sighting
Every sighting in Washington County, MN maps the invasion front. Report directly to Minnesota Dept of Agriculture (MDA).
Report Now →Squish on Sight
See a spotted lanternfly? Kill it immediately — it is legal and encouraged in all states. Learn the best kill methods.
Full Fight Guide →Map ToH in Your Block
Tree of Heaven removal cuts off SLF food supply. Add ToH sightings to the community map to guide removal efforts.
View Sighting Map →Statewide resources
Full MN State Guide
County-level data, quarantine zones, treatment guides, and agency resources for the entire state.
See the full MN guide →Community intelligence
Live Sighting Map
See where SLF has been spotted near you in Washington County, MN. Add your own sighting to help map the front.
Open the Map →Free weekly fight briefing
Fight SLF in Washington County, MN.
One email per week. Your zip code. Your threat level. Your action plan. Know exactly what to do this week in Washington County, MN.