Valmiki Ramayana Kishkindha Kanda Sarga 53 Shloka 18
Original Shlokaते वसन्तमनुप्राप्तं प्रतिबुद्ध्वा परस्परम्। नष्टसन्देशकालार्था निपेतुर्धरणीतले।।4.53.18।।
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ते they, वसन्तम् spring, अनुप्राप्तम् set in, परस्परम् with one onather, प्रतिबुद्ध्वा after realising, नष्टसन्देशकालार्थाः having exceeded the time set, धरणीतले on the ground, निपेतुः fell down.
Having realised (looking at the flowers) that spring has set in and they have exceeded the time limit, they all fell down on the ground.