Looks like it is a single stamp, not part of a set and named Friendship Garden. It must have been available prior to 2007 as that's the oldest copy of a catalogue that I have.
This single stamp was sold in the 1998-1999 Stampin Up! catalog. It is called Friendship Gardens. There was a stamp set that went with it that was called Flowers Give Pleasure. I wish i would have bought them both. Very cute!!