This checks out, although it isn't listed. Here is the story: "One of her greatest known miracles occurred when she was still alive, the miracle of roses. It is said that during one of her many trips delivering bread to the poor in secret, Ludwig met with her and asked her questions to erase everyone's suspicions that she was stealing treasures from the castle. He asked her to reveal the contents under her cloak, and as she did a vision of white and red roses was seen. To Ludwig, this meant God's protection was evident. In other versions, it was her brother-in-law who found her. Elizabeth's story is one of the first of many that associates Christian saints with roses." https://www.catholic.org/saints/saint.php?saint_id=45