grass used for making mats, Huanpu, place famous for robbers
萑 is a rare kanji with two distinct, unrelated meanings: a type of grass used for weaving mats, and a historical place name (Huanpu) notorious for robbers. These meanings do not share a clear conceptual center.
萑 combines 艹 (grass) with 隹 (short-tailed bird). The grass meaning likely comes from the 艹 component. The place name Huanpu is a historical Chinese usage, and its connection to the components is unclear.
Picture a short-tailed bird (隹) hiding in tall grass (艹) used for making mats. The grass is so thick that robbers could hide there, like in the infamous Huanpu.
For カン, imagine a can of woven grass mats: can -> カン, and the mats are made from the grass 萑.