also: はなめ
noun
Refers to the bud of a flower before it blooms; used in botanical and everyday contexts.
桜の花芽がふくらみ始めた。
The cherry blossom buds have started to swell.
寒さで花芽が傷んでしまった。
The flower buds were damaged by the cold.
蕾 is a more general term for bud (including leaf buds), while 花芽 specifically means flower bud.
Compound of 花 (flower) and 芽 (bud). The reading かが is the on'yomi, while はなめ is a kun'yomi reading.