| Yam, Yellow | Dioscorea villosa |
| Yarrow | Achillea millefolium |
| Yarrow, Fernleaf | Achillea filipendulina |
| Yellow-eyed-grass, Pink-based | Xyris difformis |
| Yellow-eyed-grass, Small's | Xyris smalliana |
| Yellow-eyed-grass, Twisted | Xyris torta |
| Yellow-rocket, Early | Barbarea verna |
| Yellowcress, Bog | Rorippa palustris var. palustris |
| Yucca | Yucca filamentosa |