noun
young greens; tender leaves
Refers to young, tender leaves of vegetables like mizuna, Japanese mustard spinach, or rape, often used in salads or lightly cooked dishes.
うぐいす菜をさっと茹でておひたしにした。
I quickly boiled the young greens and made ohitashi.
春になると、うぐいす菜が店頭に並び始める。
When spring comes, young greens start appearing in stores.
The name うぐいす菜 (uguisu-na) likely comes from the association of the fresh green color with the Japanese bush warbler (uguisu), a bird that heralds spring. The exact origin is uncertain.