Begonia is light red, red is "happy but not obscene", and light white is "sad but not harmful", surrounded by green leaves all over the tree. It is moderately slim, like an innocent, healthy and happy girl, and it is the creator's most proud work.
Bing Xin compared Haitang to a girl. This is personification. This sentence is an anthropomorphic sentence, not a sentence describing Haitang.