Groot's high-school years.

NegativeSoul said:

Groot's high-school years.

I saw this more of play on the concept of 'youth', 'spring' and 'new beginnings' in anime media. You'll almost always see characters with their school uniform seeing fluttering sakura petals on their entrance ceremony, so maybe the artist combined the three into one character that symbolizes them all.

-albeit a little creepy.

Another interpretation of this of youth is that the roots are not planted in the ground as of yet.