Can you clarify for me? Does she want to pick her own flowering plants or to pick actual flowers?
If she just wants to pick flowers, you might check with some of the growers at the Roch. farmer's market for contacts with flower growers. I believe there are some growers over by Lake City vs Redwing who grow cut flowers but don't know who/where...perhaps someone else here will know.
If she is wanting flowering plants we've got a ton of nice nurseries in the area both in roch and in surrounding communities.