This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development is uncertain. The modern form visually contains 赤 above 土, but the original component relationship is unclear.
The kanji combines 赤 (red) above 土 (soil). Picture red soil, but its meaning is uncertain.
For はけ, imagine a brush (刷毛, はけ) sweeping red soil: はけ -> はけ, though the kanji's meaning is unclear.