Mother always gets up early in the morning.

Literal

Mother [topic-は] always morning early wake-up.

朝早く stacks a time noun (朝) with an adverbial form of 早い, producing 'early in the morning.' No particle is required between 朝 and 早く — this is a productive pattern for tight time adverbs (朝早く, 夜遅く, 朝一番).