This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 稫 is uncertain. It combines 禾 (grain) with 畐, but the original semantic and phonetic roles are unclear.
The left side is grain 禾, and the right side 畐 looks like a full container. Picture grain growing thick and lush, filling the container to the brim.
For ヒョク, imagine a hyacinth growing thickly among the grain: hyacinth -> ヒョク, and the grain field is lush and dense.