Hmmm... wow, I've never heard of this...
Could it be the garden in France? (off to the right of the perfume shop)...
Could it be a garden that is being planted for Flower and Garden? That does start shortly after Easter... To the best of my recollection, there isn't a garden in the area of the American Adventure, just brick and cement and some trees... I give up. If anyone else knows, please post, cause I'm really curious now...