。
She picked flowers in the garden.
Literal
She [topic-は] garden [possessive-の] flowers [object-を] picked.
花を摘む ('to pick flowers') uses 摘む, which means 'to pluck/pick' — specifically the gentle action of picking flowers or buds, distinct from the more forceful 抜く (pulling) or 切る (cutting). A simple, evocative sentence.