This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The historical origin of 荗 is uncertain. It visually contains 艹 (grass) and 戍, but the exact development is unclear.
With grass 艹 above and a guard-like shape 戍 below, imagine a hidden plant that is hard to identify—its meaning remains uncertain.
For ショク, imagine a shock of grass growing over an old guard post: shock -> ショク, and the plant hides the meaning.
—