A.P.
Excellent idea! I would call your local garden center and let them know what youre plans are and I'm sure they would donate them. Nurseries also carry trees. We did this also at my high school. What I did for our 10 year was made a board (those tri-folding presentation boards) and put pictures up of those who couldnt make it due to war, out of state etc and a brief paragraph that they wrote as to what they have done and why they couldnt be there. The attendees appreciated that... and had one are (the biggest part) a memorial for a gentlemen who passed away shortly after graduation.