First, we need to understand the word being used in the sentence.
Before the yucca has come to (flower), while yet its bloom is a luxurious, creamy, cone-shaped bud of the size of a small cabbage.
From what we can tell by the use of flower in this sentence, we can tell that the yucca is blooming. Another word for blooming or flower is flourish, which means to grow. This word creates a more awe-filled tone.
Answer is B) Flourish.