So right! Go get the office to check their video surveillance cameras to see if they got pictures of the dastardly thief.
THEN call the local TV station to come and do a story on the theft. Heck, you can easily say that the value of those daylilies would be in the hundreds of dollars if you had not had them donated.
By the way, I also volunteer at our local school garden, and even though the school district never acknowledges our efforts, it's the appreciation of the teachers and kids that really counts, and they tell us every time how much the garden means to them. Don't get discouraged.