開花 and 満開: blossoms opening, talent flourishing and full bloom
Compare 開花 for plum blossoms and flourishing talent with 満開 for flowers in full bloom. Identify the object, the change and the fully blooming state in each example.
開花 as plum blossoms opening
開花 (かいか) means blooming or flourishing. 「暖かい日が続き、庭の梅が開花した。」 means “Continued warm weather brought the plum trees in the garden into bloom.” Continued warm weather and the plum trees coming into bloom are presented together.
The flowering object here is the plum trees in the garden. The reported 開花した does not describe other flowers reaching full bloom or all their blossoms falling.
Talent as the object of 開花
「長年磨いた才能が大きな舞台で開花した。」 means “A talent honed for years flourished on a major stage.” This is the figurative flourishing of a talent honed over years, not an event of growing a plant.
The plum blossoms and 才能 occur with the same 開花した but name different objects. In the talent example, read the expressed flourishing rather than assigning a plant growth stage or flowering date.
満開 as full bloom and the object of admiration
満開 (まんかい) means full bloom. 「公園の桜が満開になった。」 uses になった for the change into full bloom. The English translation says, “The cherry trees in the park are in full bloom.” It presents the resulting state.
「満開の花を窓辺から静かに眺めた。」 means “I quietly admired the fully blooming flowers from the window.” Distinguish the flowers' fully blooming state from the person's act of admiring them. These examples do not establish that every instance of 開花 has already reached full bloom.
What is flowering in 才能が大きな舞台で開花した and 桜が満開になった?
Show the answer and why
The first describes honed talent figuratively flourishing on a major stage; the second describes cherry blossoms reaching full bloom. The talent is not a literal plant, and the examples do not make every instance of 開花 an already fully blooming state.