This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 荖 is uncertain. It visually combines 艹 (grass) and 老 (old), but the original meaning and component relationship are unclear.
The top grass radical 艹 and bottom old 老 suggest an old plant, but the actual meaning is unclear. Picture an ancient, withered plant that has lost its original identity.
For ハイ, imagine an old plant letting out a sigh: 'hai...' The sighing sound ハイ echoes the kanji's uncertain, faded meaning.