Once you raise the Sapling to level 14, you'll get a ticket at the end of the event that lets you trade for a garden character of your choice of Saplings including all the originals plus the new skin for the Red Sapling if you want that.
That's all I know.
They got some new thing going on the daily 100DMM pt gachas where you get a half Centy if you get 10 in a week. Next a full Centy and additional half Centy if you buy more. It resets weekly for the next few weeks. This is addition to the RG tickets.