This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 荓 is uncertain. It visually contains 艹 (grass) and 并, but the original semantic and phonetic roles are unclear.
The top is grass 艹, and the bottom 并 looks like a pair of things joined together. Imagine a rare, unnamed plant with paired leaves.
For ヘイ, picture a patch of hay (ヘイ) where this mysterious grass grows: hay -> ヘイ.
—