。
She likes arranging flowers.
Literal
She [topic-は] flower [object-を] arrange [nominalizer-の] [subject-が] like is.
生ける ('to arrange flowers, to bring to life') is the same root as the noun 生け花 (ikebana) — Japan's centuries-old art of flower arrangement, codified into multiple schools (池坊, 草月, 小原…). Less about decorative abundance than about line, asymmetry, and seasonal feeling, ikebana developed in tandem with Buddhist temple offerings and the tea ceremony. Saying 花を生ける rather than 花を飾る ('decorate with flowers') subtly signals that this is the formal, considered art rather than just sticking blooms in a vase. Polite ~です keeps the register friendly.