SM Releases Another Clue to Their "Winter Garden" Project

SM Entertainment revealed its second image teaser for its special winter project, titled “Winter Garden.”

The first teaser showed a plant with three flowers, each with a number written on it – 15, 18, 22 – leading many to believe those were the dates of the singles release. Earlier today, industry insiders revealed that f(x) was the first group to release a single on December 15 for the project, with SM confirming that f(x) was part of it the project with further details to be given later.

That later is now, with SM Entertainment revealing a new teaser image just minutes ago.. It is the same plant as in the first one, except the flowers are now red and there are letter on it instead of numbers:  F, R, and B.

The teaser, in connection with the first one, could be revealing that on December 15, f(x) will release a single; on December 18, Red Velvet will release a single; and finally on December 22, BoA will release a single.

What do you think the letters mean?