To cause plants or vegetation to wither or die (to let dry); also to dry/season wood for use.
うっかりして観葉植物に水をやり忘れ、枯らしてしまった。
I forgot to water the houseplant and ended up killing it.
建築用の一部の材木は虫害を防ぐために十分に枯らしてから使う。
Some construction lumber is thoroughly seasoned (dried) before use to prevent insect damage.
農薬を強く撒きすぎて苗を逆に枯らしてしまった。
I sprayed too much pesticide and ended up killing the seedlings.