This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 蘐 is uncertain. It visually contains 艹 (grass) and 諼, but the original component relationships are unclear.
With no clear meaning, picture the grass radical 艹 covering a complex lower shape like a tangled thicket of unknown plants.
For ケン, imagine a person named Ken trying to identify the mysterious plant: Ken -> ケン, but even Ken cannot figure out its meaning.