The so-called national flower "Huizhi" is purely the product of some people's YY, and all the news that can be found comes from the same post.
It is true that plum blossom and peony are more likely to be elected as national flowers (or more competitive).
Reference source:
Culture/Weekend/2009-03/05/content _17384056.htm
/system/2008/05/3 1/00333986 1 . shtml
Welcome to Wikipedia's national flower entry.