We replaced the lawn with evergreen grass to keep it green year-round.
私たちは一年中緑を保つために庭を常緑の芝に替えた。
常緑の芝、つまり一年中緑を保つ庭の芝生や牧草を指す
Grass or turf that remains green throughout the year, used for lawns or pasture and selected for year‑round greenness.
evergreen grassは、evergreen(常緑の)+grass(草)という複合から成り、常に緑色を保つ芝や牧草を表す表現。