Finding the details
Start with the obituary. Most funeral homes post obituaries online, and they usually list the visitation, service and burial with dates, times and places. A search for the person's full name and town often finds it. Local newspapers and church websites may post it too.
If there is no obituary yet, ask a family friend or the family's church. It can take a day or two for service plans to be set. It is fine to wait and call the florist once you know.
When you call, give the florist the person's full name and whatever you know. Local florists deliver to area funeral homes often and may be able to help confirm details. If you never find the service, sympathy flowers to the home are always appropriate.