Gucci always seem to make things so difficult to research. There are basically not one but two Gucci Garden capsule collections. I went to an event in London 2016 (piano music, dried flowers, potpourri gift bags) that took place at flagships across the world. There was also a capsule online only collection full of flowers, Your bag is not part of that collection. The Dionysus bags that come from that collection are very floral (also very nice).
So Gucci Garden was a 2016 'thing' 2 years before Gucci Museo (Museum) in Florence was renamed 'Gucci Garden'. Your bag comes from the collection Summer 2018 that launched the renaming of the museum (living 'garden' hardy parental classics'/new flowers/weeds/ garden of Eden/Gucci bees and snakes in the Flora/ blah blah). Bjork opened Gucci Garden with a performance wearing a custom gown. It wasn't an opening but a renaming/re-thinking because Alessandro Michele didn't like the idea of a museum, he wanted something living.
Isabella Cotier came up with some BS story about being inspired by a crazy-acting woman she knew in Florence called Flora (what are the odds?).
Apart from her illustrated art merch, there were also pink hoodies, pink everything including tea towels and Dionysus bags (Small and Med in pink white and black) all issued to commemorate Gucci Garden in Florence (that's basically a museum).
I'm sure you will find PR for the 2018 opening of the Gucci Garden in Florence. Pics of your bag will be there somewhere.