I was at the post office last week and saw that a new stamp issue was coming up. It has been 50 years since the start of the campaign to green Singapore. A special stamp issue to commemorate this was released on 13 July 2013. What was special about the stamps is that seeds come with the stamp. See the black dots on the local stamp. Those are the seeds of the Portulaca plant (with pink flowers) which is also shown on the local stamp.
I am going to plant them to see if it will grow.