On the subject of 柳 (willow)
For the mnemonic it used the radical stamp and tree - however for me the right hand side is a slightly slightly disgruntled cat pirate? and wanikani seems to ignore that.
‘If you cause a cat pirate to be disgruntled and out of shape, if will inevitably take shelter up a willow tree. The branches of a willow are dense and provide good shelter whilst recovering’
just thought is was weird the middle bit of the kanji was overlooked - or perhaps i’m missing something.