Based on 960 research-grade iNaturalist flowering observations in Indiana, Prairie Trillium blooms mainly from April to May, peaking in April. It ranks #2 among wildflowers recorded in the state in our data.
Trillium recurvatum
Prairie Trillium in Indiana by month
Bars show research-grade observations per month. They mix true seasonality with how often people are outdoors, so treat small numbers with caution.
Also in bloom in Indiana in April

Dutchman's breeches
Virginia Springbeauty

Bloodroot

Yellow Trout Lily

Virginia bluebells
Toadshade

Squirrel Corn

Henbit Deadnettle
Places to look in Indiana
Turkey Run State Park
Brown County State Park
Prophetstown State Park
National ForestHoosier National Forest
Mounds State Park
Falls of the Ohio State Park
FAQ
When does Prairie Trillium bloom in Indiana?
Mainly April–May, with the most records in April.
How common is Prairie Trillium in Indiana?
It ranks #2 by number of iNaturalist flowering observations among wildflowers in Indiana (960 records in our sample).