garden, yard, farm
薗 centers on a cultivated outdoor space: a garden, yard, or farm where plants are grown.
薗 is a variant form of 園, adding the grass radical 艹 on top to emphasize vegetation. The core 園 combines 囗 (enclosure) with 袁 (phonetic), suggesting an enclosed cultivated space.
The grass radical 艹 sits above 園 (garden), like extra lush plants growing over the garden wall. Together they make a garden or farm full of greenery.
For エン, picture the garden as the end of a long path: end -> エン, and you arrive at the lush 薗.