This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
蘩 combines the grass radical 艹 with 繁, which likely contributes sound. The exact historical development is uncertain.
The grass radical 艹 over 繁 suggests a plant, but the specific meaning is uncertain. Picture a lush, overgrown plant that is hard to identify.
For ハン, imagine a hand (ハン sounds like 'hand' without the 'd') reaching into the grass to pull out this mysterious plant.