expression
all things have the Buddha nature
A Buddhist phrase from the Nirvana Sutra expressing the doctrine that even insentient beings such as plants and the land itself possess Buddha-nature and can attain enlightenment.
See also: 大般涅槃経
「草木国土悉皆成仏」は、大般涅槃経に由来する考え方です。
"Sōmoku kokudo shikkai jōbutsu" is a concept originating from the Mahāparinirvāṇa Sūtra.
From the Nirvana Sutra (大般涅槃経). The phrase is a Sino-Japanese reading of the Chinese translation of the sutra passage.