spinach
菠 refers specifically to spinach, a leafy green vegetable. It is used almost exclusively in the compound 菠薐草 (ほうれんそう) for spinach.
菠 is a phono-semantic compound: the grass radical 艹 indicates a plant, while 波 (ハ) provides the sound. It was created to represent spinach, a plant introduced to China and Japan.
The grass radical 艹 on top tells you it's a plant, and the 波 (wave) underneath can remind you of the wavy, crinkled leaves of spinach.
For ハ, imagine a hearty laugh: "Ha!" when you see a big pile of spinach. Ha -> ハ.
pineapple bun (Chinese sweet pastry similar to the Japanese melonpan); bolo bao