You learn the kanji 花 (hana) or “flower” at the beginning of your kanji study. If you take this character apart, it can be divided into 廾 (kusakanmuri) and 化 (ka). Back in the day people must have thought, “the green leaves transform into red and white.” That’s why the symbol transformed as “the 草（廾）(kusa) that changes”.
How about when a 木 (ki) or “tree” transforms 花 (hana) or “flower” like? It becomes the kanji 椛 (momiji). In autumn, the maple leaf changes into red and yellow colors like a flower. The Japanese made this character 椛 by describing the appearance.
Be honestly, I didn't know the character 椛 but it's quite interesting and beautiful way how it has been created. I've never imagine that a tree could transforms into a flower.