When do cattails bear their cylindrical brown blooms? What month of the year? are they native to river banks in Indiana?
Please do your homework well and get your cattail ID confirmed. Many cattails in Indiana are invasive species. https://www.nps.gov/rlc/greatlakes/upload/CATTAILS-for-website.pdf
Cattails are produced in late summer.
This link has information on Cattails in Indiana wetlands.