ligustrum sinenese, tree
杻 refers to a specific type of tree, identified as Ligustrum sinense (Chinese privet). Its meaning is narrow and botanical, with no clear broader conceptual center beyond the tree itself.
杻 combines 木 (tree) with 丑, which likely serves as a phonetic component. The exact historical development is uncertain.
The tree radical 木 beside 丑 suggests a specific tree. Picture a twisted, gnarled privet tree with a shape that reminds you of the character 丑.
For チュウ, imagine chewing a leaf from this tree: chew -> チュウ, and the privet leaf has a distinctive taste.